Hindawi Publishing CorporationInternational Journal of Antennas and PropagationVolume 2013 Article ID 405943 8 pageshttpdxdoiorg1011552013405943

Research ArticleA Reconfigurable WiMAX Antenna for Directional andBroadside Application

M Jusoh1 M F Jamlos1 M R Kamarudin2 and T Sabapathy1

1 Advanced Communication Engineering Centre (ACE) School of Computer and Communication EngineeringUniversiti Malaysia Perlis (UniMAP) Kampus Pauh Putra Arau 02600 Perlis Malaysia

2Wireless Communication Centre (WCC) Faculty of Electrical Engineering Universiti Teknologi Malaysia (UTM)Skudai 81310 Johor Malaysia

Correspondence should be addressed to M Jusoh ame tango1yahoocom

Received 28 February 2013 Accepted 25 April 2013

Academic Editor Mohd Tarmizi Ali

Copyright copy 2013 M Jusoh et alThis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A novel reconfigurable compact patch array antenna for directional and broadside application is proposed The presented antennahas successfully been able to function for directional beam at 320∘ or 35∘ and divisive broadside beam at 43∘ and 330∘This is realizedin the unique form of aperture coupled spiral feeding technique and positioning of the radiating elements at 0∘ 90∘ and 180∘ Theswitchable feature is effectively performed by the configuration of three PIN diodes All PIN diodes are positioned at the specificlocation of the aperture coupled structure It is discovered in simulation that the switches can be represented with a copper strip lineor touchstone (TS) block The proposed antenna design operates at 237GHz to 241 GHz and has a maximum gain of 64 dB andefficiency of 8597 Such antenna produces a broadside HPBW with a wider bandwidth covering from minus90∘ to 90∘ compared tothe normal microstrip antenna which could only provide HPBWof minus50∘ to 50∘ Moreover the proposed antenna has small physicaldimension of 100mm by 100mm The simulation and measurement results have successfully exhibited the idea of the presentedantenna performance Therefore the antenna is sufficiently competent in the smart WiMAX antenna application

1 Introduction

In light of the rapid growth of wireless technology therequirement of an antenna with a higher data rate robust tointerference and minimum bit error rate (BER) is exception-ally crucial [1] Therefore a special antenna design with anenhancement of the antenna performance is the main chal-lenge A switched beam or adaptive array antenna could bethe solution Recently switched beamhas gained a huge atten-tion among the researchers and industrial players Owing tothis it is important to design a switchable beam antenna withthe ability to direct the main beam towards the desired signalwhile suppressing the antenna beam in the direction of theunwanted signal

The fast-growing technology in microstrip antennas hasled numerous researchers on the study of reconfigurablebeam patch antenna [2ndash4] Ali et al [2] Proposed a recon-figurable planar antenna array (RPAA) by integrating withparasitic elements to achieve a beam steering capability

The reconfigurable ability is realized using a PIN diode switchto steer the beam to the desired direction angles of minus30∘00∘ and 20∘ Yusuf and Gong [3] achieved a beam steeringdirection angle of minus20∘ to +20∘ with five different reactiveloading values In that work a low-cost patch antenna withcenter element excited by 50Ω inset current has driventwo neighboring elements via a mutual coupling effect Thispatch antenna was fabricated and measured at a frequency of3GHz Antenna in [4] successfully obtained two dedicatedangles of 0∘ and 270∘ with activation of probe 1 and probe 2respectively The hollow cylindrical dielectric pellet antennawith permittivity of six has been designed to operate at thefrequency resonant of 953GHz and 111 GHz

This paper demonstrates a novel antenna design withreconfigurable beam of directional and divisive broadsideapplicationThe proposed antenna has the capability to directits radiation pattern to 320∘ and 35∘ at a particular predefinedswitches Moreover the divisive broadside can cater directionat 43∘ and 330∘ Therefore the proposed antenna with

2 International Journal of Antennas and Propagation

2300

2330

2360

2390

Peninsular Malaysia

25

30 30 30Sabah and Sarawak

2375

2400

REDtone-CNX

Asiaspace 119884-max PacketOne

World Interoperability for Microwave Access (WiMAX 23 GHz)

Figure 1Malaysian SpectrumAllocationChart ofWiMAX23GHz[5]

a wider HPBWwhich can be covered in minus90∘ to +90∘ is bettercompared to the similar performance of antennas as dis-cussed in [6 7] Furthermore each direction has successfullyachieved a maximum beam direction of 335 dBi 321 dBiand 280 dBi respectively To the best of our knowledgenone of reconfigurable beam antenna has achieved peak gainperformance at all reconfigurable beam direction [8 9]

The reconfigurable radiation pattern is achieved by theconfiguration of the radio frequency switches (R-RFS)Theo-retically the switchable antenna can be realized by using radiofrequency (RF) switches such as PIN diodes varactor diodesMEMs and GaAs FETs The changes of these device statesldquoONrdquo and ldquoOFFrdquo at the specific position would function asa frequency tuning [10 11] or act as a impedance-matchingdevices [12 13]

In terms of size the proposed antenna with the dimen-sions of 100mmtimes 100mm is smaller than the conventionalmicrostrip antenna with the similar performance [2 14ndash16]Another unique benefit of the proposed antenna lies in itsdesign It is discovered on the proposed antenna that the spi-ral feed line with various aperture slot dimensions and posi-tions has significantly contributed to the successfulness of thedirections and divisive beam performance Moreover thesequence radiating element placement of 90∘ 180∘ and 270∘also leads to the achievement of reconfigurable beam capabil-ity Besides that the proposed aperture coupled technique hasseparated the radiating element and the feeding network thateventually contributed to the reduction of the spurious effectTherefore the efficiency of the power transfer between theradiating and feed structure is really significant [17]The pro-posed antenna design in this wok applied a rectangular aper-ture slot that helps to couple the electromagnetic (EM) fromthe field of the radiating element and leads to the optimumantenna performance

The proposed antenna has successfully achieved a con-siderable performance at particular resonance frequency of239GHz over 237 to 241 GHz impedance bandwidth underthe tolerable reflection coefficient of 119878

11lt minus10 dB With

numerous advantages the proposed antenna is suitable forWorld Interoperability for Microwave Access (WiMAX)application regulated by Malaysian and Multimedia Com-mission (MCMC) [5] As depicted in Figure 1 the proposed

antenna operates in the range of Packet One telecommunica-tions provider 236GHz to 239GHz for the use in Peninsu-lar Malaysia

The remainder of this paper is organized as follows InSection 2 the antenna radiating element and the aperturecoupled feed technique are explained Besides that the inte-gration of the three RF PIN diode switches at the three spiralarm feeds is investigated The antenna measurement andsimulation comparison of the reconfigurable radiation pat-tern reflection coefficient and gain are presented inSection 3 Finally conclusions are drawn in Section 4

2 Antenna Design and RF PINDiode Configuration

Figure 2 depicts the configuration of the proposed antennadesign This simulated design has been performed by Com-puter Simulation Technology (CST) software as CST is com-petence 3D electromagnetic simulation software [18] Theproposed antenna is developed from an aperture coupledfeeding technique Technically this technique is denoted as amultilayermethodwhich separates the radiating element andthe feeding network as shown in Figures 2(a) and 2(b)Thus aspurious effect is minimized which eventually increasing theantenna efficiency Figure 2(a) illustrates a simulated geome-try of the three radiating elements on the upper substrate Allthe rectangular radiatings have similar dimensions of 38mmby 16mm It is discovered in simulation in order to achievea reconfigurable beam capability that the radiating elementsshould be positioned in a sequent spiral manner of 90∘ 180∘and 270∘ Meanwhile the lower substrate deployed on bothsides consists of aperture slots and spiral feed line as indicatedin Figures 2(b) and 2(c) respectively

Working principle of the proposed antenna aperturecoupled feeding shows that the optimum dimension andposition of aperture slot is ultimately crucialThis determinesthe amount of power transferred from the antenna spiral feedline to the radiating elementHence the reflected power at thesource is minimizedTherefore the performances of the pro-posed antenna such as gain efficiency and radiation patternare preserved to be optimal Presented antenna implementeda rectangular aperture slot with dimension of 144mm by125mm placed at 10mm away from the edge of the rectan-gular radiating arm The slots dimension can be obtained byresolving the following [1 17]

119871

119904= 001120582

119900

119882

119904= 0115120582

119900

120582

119900=

119888

119891

(1)

As shown in Figure 2(c) the switchable antenna isachieved by integrating the RF switches to the antenna spiralfeed arm (S-Arm) instead of the radiating elementThis helpsto minimize power deteriorations by the introduction of thesurface mount component (SMC) [10 11 14ndash16] Switches AB and C are placed at the optimum location of S-Arm 1

International Journal of Antennas and Propagation 3

100 m

m

100 m

m

100 m

m100 mm

(a) (b)

(c)

S-Arm 3

S-Arm 1

S-Arm 2

Inputimpedance

A B

C

PIN diodeR-RFS

119909

119910

119911 119909

119910

119909

119910

100 mm100 mm

Upper substrate-TaconicLower substrate-Taconic

Figure 2 Structure of the simulated antenna (a) Radiating element surface (b) Rectangular slot aperture coupled (c) Spiral feed line arrange-ment

1 2 3

4

119909

119910

(a)

1

1

1

1

1

2 2

2

2

3

4

Diode ON states2p

1998400

2998400

3998400

4998400

Diode OFF states2p

Diode OFF states2p

(b)

Figure 3 Schematic diagram of the TSB implementation to the antenna (a) Port creation of the antenna design (b) TSB attached to theantenna

S-Arm 2 and S-Arm 3 respectively The R-RF switchesconfiguration of ON state indicates that more RF currentwill surge to the radiating element In contrast the OFFstate condition causes gap between the middle line and therespective S-Arm which lead to no current flow through thegap Such circuit configuration can be considered as circuitmaker or a circuit breaker This concept is proven throughsimulation by representing R-RF switches with a copper stripline or a touchstone (TS) block The presence of the copperstrip shows that R-RF switches in ON state and vice versa

TS denoted as SnP file is an ASCII text file used fordocumenting the n-port network parameter data of anactive device or passive interconnect network This SnP fileof the deployed BAR50-02V PIN diode is obtained fromthe manufacturerrsquos website [19] Based on the simulationresult the antenna performance can be predicted beforethe optimized antenna design is fabricated with the surfacemount component (SMC)

Figures 3(a) and 3(b) show the schematic diagram of theTS implementation to the antenna Firstly the discrete portis drawn from the source edge to the passive edge whereall antennarsquos R-RF switches are positioned TS consists oftwo blocks (1) diode ON state and (2) diode OFF state InCST schematic the TS is imported and positioned to the

0

minus5

minus10

minus15

minus202 22 24 26 28 3

Frequency (GHz)

Refle

ctio

n co

effici

ent (

dB)

Copper strip lineTS

Figure 4 Comparison of the simulated reflection coefficient result

desired predefined reconfigurable state Such configuration isdepicted in Figure 3 where the source port defined as port 1switch A as port 2 (diode ON state) switch B as port 3(diode ON state) and switch C as port 4 (diode ONstate) Figure 4 illustrates the comparison of the 119878

11result of

4 International Journal of Antennas and Propagation

(a)

PIN diode

C1

C2

L1

L2

(b) (c)

Figure 5 Geometry of the fabricatedantenna structure (a) Radiating element surface (b) Spiral feed network integrates with RF switches(c) Antenna layout

Table 1 PIN diode switches configuration of the measured and simulated antenna

Type of switch Number of PINdiode switch PIN diode status

Reconfigurable RFswitches (R-RFS)

A OFF ON ON

B ON ON OFF

C ON ON ONSimulated peak beam angle 340∘ 30∘ 50∘ and 325∘

Measured peak beam angle 320∘ 35∘ 43∘ and 330∘

Simulated total antenna efficiency 8368 8374 8597Measured total antenna efficiency 758 764 782

Simulated gain (dBi) 6281 5542 5154Measured gain (dBi) 335 321 280

Simulated HPBW (degree) 69∘ 1229∘ 703∘

Type of radiation pattern Directional beam Divisive broadside

the antennawith TS and antennawith copper strip line FromFigure 4 the TS reflection coefficient result has shifted tothe left approximately 10MHz with reflection to the copperstrip line resonant frequency of 239GHz Besides the secondharmonic of TS technique is bigger compared to the copperstrip line Moreover the impedance matching for TS is bettercompared to the copper strip line Overall the performanceof both techniques is slightly different due to some powerexcited has been absorbed by the PIN diode

Figure 5 shows the fabricated antenna with integrationof RF switching circuit into its spiral feeding network TheR-RF switches circuit is developed from the surface mountcomponent (SMC) It consists of one PIN diode two DC(direct current) block capacitors two RF choke inductorsand a DC supply The DC source is inserted to the inductorthat performed as a short circuit However the capacitoronly allows the alternating current (AC) to pass throughinstead of choke the DCTherefore the DC flows in the otherdirection and ON the PIN diode The DC supply of 5 volts isinduced through the white wire and shorted to the groundvia the black wire The predefined reconfigurable directionto a desired application can be controlled via the ldquoONrdquo andldquoOFFrdquo switches as tabulated in Table 1

Throughout the research allmeasurement processeswerecarried out in the Antenna and Microwave Lab (AMREL-LAB) of Universiti Malaysia Perlis (UniMAP) with the helpof Agilent Technologies E5071C (9 kHz to 85GHz) Net-work Analyzer and 3D2D Atenlab Anechoic Chamber Asdepicted in Figure 6 the antenna under test (AUT) performsas a transmitter and a double ridged horn antenna functionsas a receiverThe line of sight (LOS) between the antenna andthe receiver is kept at 30m

3 Results and Discussion

The measurements show that the proposed antenna hassuccessfully achieved aminimum reflection coefficient of lessthan minus10 dB (119878

11lt minus10 dB) With certain R-RFS configura-

tion the return loss of 239GHz is stated atminus184 dBminus183 dBand minus27 dB as shown in Figures 7(a) 7(b) and 7(c) respec-tivelyThose figures indicate that the 90power that has beentransmitted is contributed by proper alignment between theproposed antenna spiral feed line (bottom substrate) and itsradiating elements (top substrate)

A sufficient interelement spacing (IES) of the proposedantenna for three R-RFS arrangements is proven through

International Journal of Antennas and Propagation 5

Proposed antenna

Receiver

(a)

AUT

(b)

Receiver

(c)

Figure 6 Positions of the proposed antenna in the anechoic chamber (a) Point-to-point positioned (b)The proposed antenna (c) Receiver(double ridged horn) antenna

the surface current distribution In Figure 8(a) it is observedthat more inset current has flown to the radiating elementsnumber two and three when R-RFS B and C are ON Lesscurrent has been attracted to the adjacent radiating elementnumber one Figure 8(b) depicts that all radiating elementsfunctioned properly after receiving a number of excitedcurrents from the SMA port Radiating element numbertwo has approximately null current distribution as shown inFigure 8(c) This leads to more current surge in the elementsnumber one and three Generally the presented antenna hasgood antenna isolation and eventually enhanced the radiationefficiency and antenna efficiency to more than 85 and 83respectively

Figures 9 and 10 depict the simulated 3D and measuredradiation pattern of the PIN diode switches configurationIt is realized in both figures that the pattern is radiatedon the 119911-119910 axis at the resonant frequency of 239GHz forWiMAX application The proposed antenna achieved thereconfigurable pattern by controlling the R-RFS switcheswiththe implementation of the spiral feed arm design Spirallingfeed with the rectangular radiating element at the positionof 0∘ 90∘ and 180∘ contributed to the phase shift of the EMwave Moreover the main lobe radiation can be tuned tothe desired direction with certain R-RFS configuration assummarized in Table 1 The high gain measurements andsimulations of the proposed antenna can be attributed to thegood coupling from the feed line to the radiating surfacethrough the appropriate size position and shape of apertureslots The measurements show a very good agreement withsimulations where the radiation patterns are formed suc-cessful with respect to the directional and divisive broadsidebeam characteristics

Figures 10(a) and 10(b) show the measured polar direc-tional radiation pattern with the normalized value As R-RFSB and C are ON the antenna radiation pattern is directed to320∘ with a gain of 335 dBi and HPBW of 69∘ as revealed inFigure 10(a) Figure 10(b) depicts the antenna beam pointedto 35∘ with a gain of 321 dBi and HPBW of 1229∘ whenall R-RFSs are ON Figure 10(c) demonstrates the divisivebroadside radiation pattern headed to 43∘ and 330∘ with again of 280 dBi andHPBWof 703∘ by turningON the R-RFSA and C It is realized that the directional beam has a betterpeak gain of 335 dBi and 321 dBi compared to the broadsidebeam with maximum gain of 280 dBi Based on the resultthe proposed antenna is able to cater for the existence of theWiMAX user between 90∘ and minus90∘ by directing the beam tothe wanted user direction

4 Conclusion

A novel patch array antenna design with directional anddivisive broadside characteristic is proposed The antennaapplied an aperture coupled feed network in order to reducethe signal deterioration due to the implementation of the R-RFS It is discovered that a spiral feed design effectively con-tributed to the achievement of the reconfigurable radiationpattern Through certain R-RFS configuration of the spiralfeed arm the proposed antenna is able to direct its radiatingbeam to the angles of 320∘ or 35∘ and divisive broadside atdirections of 43∘ and 330∘ Therefore the proposed antennawith a wider HPBW can cover the subscriber in the rangebetween minus90∘ to +90∘ For all PIN diode arrangements theantenna well performed at resonant frequency of 239GHz

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

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International Journal of

2 International Journal of Antennas and Propagation

2300

2330

2360

2390

Peninsular Malaysia

25

30 30 30Sabah and Sarawak

2375

2400

REDtone-CNX

Asiaspace 119884-max PacketOne

World Interoperability for Microwave Access (WiMAX 23 GHz)

Figure 1Malaysian SpectrumAllocationChart ofWiMAX23GHz[5]

a wider HPBWwhich can be covered in minus90∘ to +90∘ is bettercompared to the similar performance of antennas as dis-cussed in [6 7] Furthermore each direction has successfullyachieved a maximum beam direction of 335 dBi 321 dBiand 280 dBi respectively To the best of our knowledgenone of reconfigurable beam antenna has achieved peak gainperformance at all reconfigurable beam direction [8 9]

The reconfigurable radiation pattern is achieved by theconfiguration of the radio frequency switches (R-RFS)Theo-retically the switchable antenna can be realized by using radiofrequency (RF) switches such as PIN diodes varactor diodesMEMs and GaAs FETs The changes of these device statesldquoONrdquo and ldquoOFFrdquo at the specific position would function asa frequency tuning [10 11] or act as a impedance-matchingdevices [12 13]

In terms of size the proposed antenna with the dimen-sions of 100mmtimes 100mm is smaller than the conventionalmicrostrip antenna with the similar performance [2 14ndash16]Another unique benefit of the proposed antenna lies in itsdesign It is discovered on the proposed antenna that the spi-ral feed line with various aperture slot dimensions and posi-tions has significantly contributed to the successfulness of thedirections and divisive beam performance Moreover thesequence radiating element placement of 90∘ 180∘ and 270∘also leads to the achievement of reconfigurable beam capabil-ity Besides that the proposed aperture coupled technique hasseparated the radiating element and the feeding network thateventually contributed to the reduction of the spurious effectTherefore the efficiency of the power transfer between theradiating and feed structure is really significant [17]The pro-posed antenna design in this wok applied a rectangular aper-ture slot that helps to couple the electromagnetic (EM) fromthe field of the radiating element and leads to the optimumantenna performance

The proposed antenna has successfully achieved a con-siderable performance at particular resonance frequency of239GHz over 237 to 241 GHz impedance bandwidth underthe tolerable reflection coefficient of 119878

11lt minus10 dB With

numerous advantages the proposed antenna is suitable forWorld Interoperability for Microwave Access (WiMAX)application regulated by Malaysian and Multimedia Com-mission (MCMC) [5] As depicted in Figure 1 the proposed

antenna operates in the range of Packet One telecommunica-tions provider 236GHz to 239GHz for the use in Peninsu-lar Malaysia

The remainder of this paper is organized as follows InSection 2 the antenna radiating element and the aperturecoupled feed technique are explained Besides that the inte-gration of the three RF PIN diode switches at the three spiralarm feeds is investigated The antenna measurement andsimulation comparison of the reconfigurable radiation pat-tern reflection coefficient and gain are presented inSection 3 Finally conclusions are drawn in Section 4

2 Antenna Design and RF PINDiode Configuration

Figure 2 depicts the configuration of the proposed antennadesign This simulated design has been performed by Com-puter Simulation Technology (CST) software as CST is com-petence 3D electromagnetic simulation software [18] Theproposed antenna is developed from an aperture coupledfeeding technique Technically this technique is denoted as amultilayermethodwhich separates the radiating element andthe feeding network as shown in Figures 2(a) and 2(b)Thus aspurious effect is minimized which eventually increasing theantenna efficiency Figure 2(a) illustrates a simulated geome-try of the three radiating elements on the upper substrate Allthe rectangular radiatings have similar dimensions of 38mmby 16mm It is discovered in simulation in order to achievea reconfigurable beam capability that the radiating elementsshould be positioned in a sequent spiral manner of 90∘ 180∘and 270∘ Meanwhile the lower substrate deployed on bothsides consists of aperture slots and spiral feed line as indicatedin Figures 2(b) and 2(c) respectively

Working principle of the proposed antenna aperturecoupled feeding shows that the optimum dimension andposition of aperture slot is ultimately crucialThis determinesthe amount of power transferred from the antenna spiral feedline to the radiating elementHence the reflected power at thesource is minimizedTherefore the performances of the pro-posed antenna such as gain efficiency and radiation patternare preserved to be optimal Presented antenna implementeda rectangular aperture slot with dimension of 144mm by125mm placed at 10mm away from the edge of the rectan-gular radiating arm The slots dimension can be obtained byresolving the following [1 17]

119871

119904= 001120582

119900

119882

119904= 0115120582

119900

120582

119900=

119888

119891

(1)

As shown in Figure 2(c) the switchable antenna isachieved by integrating the RF switches to the antenna spiralfeed arm (S-Arm) instead of the radiating elementThis helpsto minimize power deteriorations by the introduction of thesurface mount component (SMC) [10 11 14ndash16] Switches AB and C are placed at the optimum location of S-Arm 1

International Journal of Antennas and Propagation 3

100 m

m

100 m

m

100 m

m100 mm

(a) (b)

(c)

S-Arm 3

S-Arm 1

S-Arm 2

Inputimpedance

A B

C

PIN diodeR-RFS

119909

119910

119911 119909

119910

119909

119910

100 mm100 mm

Upper substrate-TaconicLower substrate-Taconic

Figure 2 Structure of the simulated antenna (a) Radiating element surface (b) Rectangular slot aperture coupled (c) Spiral feed line arrange-ment

1 2 3

4

119909

119910

(a)

1

1

1

1

1

2 2

2

2

3

4

Diode ON states2p

1998400

2998400

3998400

4998400

Diode OFF states2p

Diode OFF states2p

(b)

Figure 3 Schematic diagram of the TSB implementation to the antenna (a) Port creation of the antenna design (b) TSB attached to theantenna

S-Arm 2 and S-Arm 3 respectively The R-RF switchesconfiguration of ON state indicates that more RF currentwill surge to the radiating element In contrast the OFFstate condition causes gap between the middle line and therespective S-Arm which lead to no current flow through thegap Such circuit configuration can be considered as circuitmaker or a circuit breaker This concept is proven throughsimulation by representing R-RF switches with a copper stripline or a touchstone (TS) block The presence of the copperstrip shows that R-RF switches in ON state and vice versa

TS denoted as SnP file is an ASCII text file used fordocumenting the n-port network parameter data of anactive device or passive interconnect network This SnP fileof the deployed BAR50-02V PIN diode is obtained fromthe manufacturerrsquos website [19] Based on the simulationresult the antenna performance can be predicted beforethe optimized antenna design is fabricated with the surfacemount component (SMC)

Figures 3(a) and 3(b) show the schematic diagram of theTS implementation to the antenna Firstly the discrete portis drawn from the source edge to the passive edge whereall antennarsquos R-RF switches are positioned TS consists oftwo blocks (1) diode ON state and (2) diode OFF state InCST schematic the TS is imported and positioned to the

0

minus5

minus10

minus15

minus202 22 24 26 28 3

Frequency (GHz)

Refle

ctio

n co

effici

ent (

dB)

Copper strip lineTS

Figure 4 Comparison of the simulated reflection coefficient result

desired predefined reconfigurable state Such configuration isdepicted in Figure 3 where the source port defined as port 1switch A as port 2 (diode ON state) switch B as port 3(diode ON state) and switch C as port 4 (diode ONstate) Figure 4 illustrates the comparison of the 119878

11result of

4 International Journal of Antennas and Propagation

(a)

PIN diode

C1

C2

L1

L2

(b) (c)

Figure 5 Geometry of the fabricatedantenna structure (a) Radiating element surface (b) Spiral feed network integrates with RF switches(c) Antenna layout

Table 1 PIN diode switches configuration of the measured and simulated antenna

Type of switch Number of PINdiode switch PIN diode status

Reconfigurable RFswitches (R-RFS)

A OFF ON ON

B ON ON OFF

C ON ON ONSimulated peak beam angle 340∘ 30∘ 50∘ and 325∘

Measured peak beam angle 320∘ 35∘ 43∘ and 330∘

Simulated total antenna efficiency 8368 8374 8597Measured total antenna efficiency 758 764 782

Simulated gain (dBi) 6281 5542 5154Measured gain (dBi) 335 321 280

Simulated HPBW (degree) 69∘ 1229∘ 703∘

Type of radiation pattern Directional beam Divisive broadside

the antennawith TS and antennawith copper strip line FromFigure 4 the TS reflection coefficient result has shifted tothe left approximately 10MHz with reflection to the copperstrip line resonant frequency of 239GHz Besides the secondharmonic of TS technique is bigger compared to the copperstrip line Moreover the impedance matching for TS is bettercompared to the copper strip line Overall the performanceof both techniques is slightly different due to some powerexcited has been absorbed by the PIN diode

Figure 5 shows the fabricated antenna with integrationof RF switching circuit into its spiral feeding network TheR-RF switches circuit is developed from the surface mountcomponent (SMC) It consists of one PIN diode two DC(direct current) block capacitors two RF choke inductorsand a DC supply The DC source is inserted to the inductorthat performed as a short circuit However the capacitoronly allows the alternating current (AC) to pass throughinstead of choke the DCTherefore the DC flows in the otherdirection and ON the PIN diode The DC supply of 5 volts isinduced through the white wire and shorted to the groundvia the black wire The predefined reconfigurable directionto a desired application can be controlled via the ldquoONrdquo andldquoOFFrdquo switches as tabulated in Table 1

Throughout the research allmeasurement processeswerecarried out in the Antenna and Microwave Lab (AMREL-LAB) of Universiti Malaysia Perlis (UniMAP) with the helpof Agilent Technologies E5071C (9 kHz to 85GHz) Net-work Analyzer and 3D2D Atenlab Anechoic Chamber Asdepicted in Figure 6 the antenna under test (AUT) performsas a transmitter and a double ridged horn antenna functionsas a receiverThe line of sight (LOS) between the antenna andthe receiver is kept at 30m

3 Results and Discussion

The measurements show that the proposed antenna hassuccessfully achieved aminimum reflection coefficient of lessthan minus10 dB (119878

11lt minus10 dB) With certain R-RFS configura-

tion the return loss of 239GHz is stated atminus184 dBminus183 dBand minus27 dB as shown in Figures 7(a) 7(b) and 7(c) respec-tivelyThose figures indicate that the 90power that has beentransmitted is contributed by proper alignment between theproposed antenna spiral feed line (bottom substrate) and itsradiating elements (top substrate)

A sufficient interelement spacing (IES) of the proposedantenna for three R-RFS arrangements is proven through

International Journal of Antennas and Propagation 5

Proposed antenna

Receiver

(a)

AUT

(b)

Receiver

(c)

Figure 6 Positions of the proposed antenna in the anechoic chamber (a) Point-to-point positioned (b)The proposed antenna (c) Receiver(double ridged horn) antenna

the surface current distribution In Figure 8(a) it is observedthat more inset current has flown to the radiating elementsnumber two and three when R-RFS B and C are ON Lesscurrent has been attracted to the adjacent radiating elementnumber one Figure 8(b) depicts that all radiating elementsfunctioned properly after receiving a number of excitedcurrents from the SMA port Radiating element numbertwo has approximately null current distribution as shown inFigure 8(c) This leads to more current surge in the elementsnumber one and three Generally the presented antenna hasgood antenna isolation and eventually enhanced the radiationefficiency and antenna efficiency to more than 85 and 83respectively

Figures 9 and 10 depict the simulated 3D and measuredradiation pattern of the PIN diode switches configurationIt is realized in both figures that the pattern is radiatedon the 119911-119910 axis at the resonant frequency of 239GHz forWiMAX application The proposed antenna achieved thereconfigurable pattern by controlling the R-RFS switcheswiththe implementation of the spiral feed arm design Spirallingfeed with the rectangular radiating element at the positionof 0∘ 90∘ and 180∘ contributed to the phase shift of the EMwave Moreover the main lobe radiation can be tuned tothe desired direction with certain R-RFS configuration assummarized in Table 1 The high gain measurements andsimulations of the proposed antenna can be attributed to thegood coupling from the feed line to the radiating surfacethrough the appropriate size position and shape of apertureslots The measurements show a very good agreement withsimulations where the radiation patterns are formed suc-cessful with respect to the directional and divisive broadsidebeam characteristics

Figures 10(a) and 10(b) show the measured polar direc-tional radiation pattern with the normalized value As R-RFSB and C are ON the antenna radiation pattern is directed to320∘ with a gain of 335 dBi and HPBW of 69∘ as revealed inFigure 10(a) Figure 10(b) depicts the antenna beam pointedto 35∘ with a gain of 321 dBi and HPBW of 1229∘ whenall R-RFSs are ON Figure 10(c) demonstrates the divisivebroadside radiation pattern headed to 43∘ and 330∘ with again of 280 dBi andHPBWof 703∘ by turningON the R-RFSA and C It is realized that the directional beam has a betterpeak gain of 335 dBi and 321 dBi compared to the broadsidebeam with maximum gain of 280 dBi Based on the resultthe proposed antenna is able to cater for the existence of theWiMAX user between 90∘ and minus90∘ by directing the beam tothe wanted user direction

4 Conclusion

A novel patch array antenna design with directional anddivisive broadside characteristic is proposed The antennaapplied an aperture coupled feed network in order to reducethe signal deterioration due to the implementation of the R-RFS It is discovered that a spiral feed design effectively con-tributed to the achievement of the reconfigurable radiationpattern Through certain R-RFS configuration of the spiralfeed arm the proposed antenna is able to direct its radiatingbeam to the angles of 320∘ or 35∘ and divisive broadside atdirections of 43∘ and 330∘ Therefore the proposed antennawith a wider HPBW can cover the subscriber in the rangebetween minus90∘ to +90∘ For all PIN diode arrangements theantenna well performed at resonant frequency of 239GHz

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

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Active and Passive Electronic Components

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RotatingMachinery

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Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

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Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

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Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

International Journal of Antennas and Propagation 3

100 m

m

100 m

m

100 m

m100 mm

(a) (b)

(c)

S-Arm 3

S-Arm 1

S-Arm 2

Inputimpedance

A B

C

PIN diodeR-RFS

119909

119910

119911 119909

119910

119909

119910

100 mm100 mm

Upper substrate-TaconicLower substrate-Taconic

Figure 2 Structure of the simulated antenna (a) Radiating element surface (b) Rectangular slot aperture coupled (c) Spiral feed line arrange-ment

1 2 3

4

119909

119910

(a)

1

1

1

1

1

2 2

2

2

3

4

Diode ON states2p

1998400

2998400

3998400

4998400

Diode OFF states2p

Diode OFF states2p

(b)

Figure 3 Schematic diagram of the TSB implementation to the antenna (a) Port creation of the antenna design (b) TSB attached to theantenna

S-Arm 2 and S-Arm 3 respectively The R-RF switchesconfiguration of ON state indicates that more RF currentwill surge to the radiating element In contrast the OFFstate condition causes gap between the middle line and therespective S-Arm which lead to no current flow through thegap Such circuit configuration can be considered as circuitmaker or a circuit breaker This concept is proven throughsimulation by representing R-RF switches with a copper stripline or a touchstone (TS) block The presence of the copperstrip shows that R-RF switches in ON state and vice versa

TS denoted as SnP file is an ASCII text file used fordocumenting the n-port network parameter data of anactive device or passive interconnect network This SnP fileof the deployed BAR50-02V PIN diode is obtained fromthe manufacturerrsquos website [19] Based on the simulationresult the antenna performance can be predicted beforethe optimized antenna design is fabricated with the surfacemount component (SMC)

Figures 3(a) and 3(b) show the schematic diagram of theTS implementation to the antenna Firstly the discrete portis drawn from the source edge to the passive edge whereall antennarsquos R-RF switches are positioned TS consists oftwo blocks (1) diode ON state and (2) diode OFF state InCST schematic the TS is imported and positioned to the

0

minus5

minus10

minus15

minus202 22 24 26 28 3

Frequency (GHz)

Refle

ctio

n co

effici

ent (

dB)

Copper strip lineTS

Figure 4 Comparison of the simulated reflection coefficient result

desired predefined reconfigurable state Such configuration isdepicted in Figure 3 where the source port defined as port 1switch A as port 2 (diode ON state) switch B as port 3(diode ON state) and switch C as port 4 (diode ONstate) Figure 4 illustrates the comparison of the 119878

11result of

4 International Journal of Antennas and Propagation

(a)

PIN diode

C1

C2

L1

L2

(b) (c)

Figure 5 Geometry of the fabricatedantenna structure (a) Radiating element surface (b) Spiral feed network integrates with RF switches(c) Antenna layout

Table 1 PIN diode switches configuration of the measured and simulated antenna

Type of switch Number of PINdiode switch PIN diode status

Reconfigurable RFswitches (R-RFS)

A OFF ON ON

B ON ON OFF

C ON ON ONSimulated peak beam angle 340∘ 30∘ 50∘ and 325∘

Measured peak beam angle 320∘ 35∘ 43∘ and 330∘

Simulated total antenna efficiency 8368 8374 8597Measured total antenna efficiency 758 764 782

Simulated gain (dBi) 6281 5542 5154Measured gain (dBi) 335 321 280

Simulated HPBW (degree) 69∘ 1229∘ 703∘

Type of radiation pattern Directional beam Divisive broadside

the antennawith TS and antennawith copper strip line FromFigure 4 the TS reflection coefficient result has shifted tothe left approximately 10MHz with reflection to the copperstrip line resonant frequency of 239GHz Besides the secondharmonic of TS technique is bigger compared to the copperstrip line Moreover the impedance matching for TS is bettercompared to the copper strip line Overall the performanceof both techniques is slightly different due to some powerexcited has been absorbed by the PIN diode

Figure 5 shows the fabricated antenna with integrationof RF switching circuit into its spiral feeding network TheR-RF switches circuit is developed from the surface mountcomponent (SMC) It consists of one PIN diode two DC(direct current) block capacitors two RF choke inductorsand a DC supply The DC source is inserted to the inductorthat performed as a short circuit However the capacitoronly allows the alternating current (AC) to pass throughinstead of choke the DCTherefore the DC flows in the otherdirection and ON the PIN diode The DC supply of 5 volts isinduced through the white wire and shorted to the groundvia the black wire The predefined reconfigurable directionto a desired application can be controlled via the ldquoONrdquo andldquoOFFrdquo switches as tabulated in Table 1

Throughout the research allmeasurement processeswerecarried out in the Antenna and Microwave Lab (AMREL-LAB) of Universiti Malaysia Perlis (UniMAP) with the helpof Agilent Technologies E5071C (9 kHz to 85GHz) Net-work Analyzer and 3D2D Atenlab Anechoic Chamber Asdepicted in Figure 6 the antenna under test (AUT) performsas a transmitter and a double ridged horn antenna functionsas a receiverThe line of sight (LOS) between the antenna andthe receiver is kept at 30m

3 Results and Discussion

The measurements show that the proposed antenna hassuccessfully achieved aminimum reflection coefficient of lessthan minus10 dB (119878

11lt minus10 dB) With certain R-RFS configura-

tion the return loss of 239GHz is stated atminus184 dBminus183 dBand minus27 dB as shown in Figures 7(a) 7(b) and 7(c) respec-tivelyThose figures indicate that the 90power that has beentransmitted is contributed by proper alignment between theproposed antenna spiral feed line (bottom substrate) and itsradiating elements (top substrate)

A sufficient interelement spacing (IES) of the proposedantenna for three R-RFS arrangements is proven through

International Journal of Antennas and Propagation 5

Proposed antenna

Receiver

(a)

AUT

(b)

Receiver

(c)

Figure 6 Positions of the proposed antenna in the anechoic chamber (a) Point-to-point positioned (b)The proposed antenna (c) Receiver(double ridged horn) antenna

the surface current distribution In Figure 8(a) it is observedthat more inset current has flown to the radiating elementsnumber two and three when R-RFS B and C are ON Lesscurrent has been attracted to the adjacent radiating elementnumber one Figure 8(b) depicts that all radiating elementsfunctioned properly after receiving a number of excitedcurrents from the SMA port Radiating element numbertwo has approximately null current distribution as shown inFigure 8(c) This leads to more current surge in the elementsnumber one and three Generally the presented antenna hasgood antenna isolation and eventually enhanced the radiationefficiency and antenna efficiency to more than 85 and 83respectively

Figures 9 and 10 depict the simulated 3D and measuredradiation pattern of the PIN diode switches configurationIt is realized in both figures that the pattern is radiatedon the 119911-119910 axis at the resonant frequency of 239GHz forWiMAX application The proposed antenna achieved thereconfigurable pattern by controlling the R-RFS switcheswiththe implementation of the spiral feed arm design Spirallingfeed with the rectangular radiating element at the positionof 0∘ 90∘ and 180∘ contributed to the phase shift of the EMwave Moreover the main lobe radiation can be tuned tothe desired direction with certain R-RFS configuration assummarized in Table 1 The high gain measurements andsimulations of the proposed antenna can be attributed to thegood coupling from the feed line to the radiating surfacethrough the appropriate size position and shape of apertureslots The measurements show a very good agreement withsimulations where the radiation patterns are formed suc-cessful with respect to the directional and divisive broadsidebeam characteristics

Figures 10(a) and 10(b) show the measured polar direc-tional radiation pattern with the normalized value As R-RFSB and C are ON the antenna radiation pattern is directed to320∘ with a gain of 335 dBi and HPBW of 69∘ as revealed inFigure 10(a) Figure 10(b) depicts the antenna beam pointedto 35∘ with a gain of 321 dBi and HPBW of 1229∘ whenall R-RFSs are ON Figure 10(c) demonstrates the divisivebroadside radiation pattern headed to 43∘ and 330∘ with again of 280 dBi andHPBWof 703∘ by turningON the R-RFSA and C It is realized that the directional beam has a betterpeak gain of 335 dBi and 321 dBi compared to the broadsidebeam with maximum gain of 280 dBi Based on the resultthe proposed antenna is able to cater for the existence of theWiMAX user between 90∘ and minus90∘ by directing the beam tothe wanted user direction

4 Conclusion

A novel patch array antenna design with directional anddivisive broadside characteristic is proposed The antennaapplied an aperture coupled feed network in order to reducethe signal deterioration due to the implementation of the R-RFS It is discovered that a spiral feed design effectively con-tributed to the achievement of the reconfigurable radiationpattern Through certain R-RFS configuration of the spiralfeed arm the proposed antenna is able to direct its radiatingbeam to the angles of 320∘ or 35∘ and divisive broadside atdirections of 43∘ and 330∘ Therefore the proposed antennawith a wider HPBW can cover the subscriber in the rangebetween minus90∘ to +90∘ For all PIN diode arrangements theantenna well performed at resonant frequency of 239GHz

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

4 International Journal of Antennas and Propagation

(a)

PIN diode

C1

C2

L1

L2

(b) (c)

Figure 5 Geometry of the fabricatedantenna structure (a) Radiating element surface (b) Spiral feed network integrates with RF switches(c) Antenna layout

Table 1 PIN diode switches configuration of the measured and simulated antenna

Type of switch Number of PINdiode switch PIN diode status

Reconfigurable RFswitches (R-RFS)

A OFF ON ON

B ON ON OFF

C ON ON ONSimulated peak beam angle 340∘ 30∘ 50∘ and 325∘

Measured peak beam angle 320∘ 35∘ 43∘ and 330∘

Simulated total antenna efficiency 8368 8374 8597Measured total antenna efficiency 758 764 782

Simulated gain (dBi) 6281 5542 5154Measured gain (dBi) 335 321 280

Simulated HPBW (degree) 69∘ 1229∘ 703∘

Type of radiation pattern Directional beam Divisive broadside

the antennawith TS and antennawith copper strip line FromFigure 4 the TS reflection coefficient result has shifted tothe left approximately 10MHz with reflection to the copperstrip line resonant frequency of 239GHz Besides the secondharmonic of TS technique is bigger compared to the copperstrip line Moreover the impedance matching for TS is bettercompared to the copper strip line Overall the performanceof both techniques is slightly different due to some powerexcited has been absorbed by the PIN diode

Figure 5 shows the fabricated antenna with integrationof RF switching circuit into its spiral feeding network TheR-RF switches circuit is developed from the surface mountcomponent (SMC) It consists of one PIN diode two DC(direct current) block capacitors two RF choke inductorsand a DC supply The DC source is inserted to the inductorthat performed as a short circuit However the capacitoronly allows the alternating current (AC) to pass throughinstead of choke the DCTherefore the DC flows in the otherdirection and ON the PIN diode The DC supply of 5 volts isinduced through the white wire and shorted to the groundvia the black wire The predefined reconfigurable directionto a desired application can be controlled via the ldquoONrdquo andldquoOFFrdquo switches as tabulated in Table 1

Throughout the research allmeasurement processeswerecarried out in the Antenna and Microwave Lab (AMREL-LAB) of Universiti Malaysia Perlis (UniMAP) with the helpof Agilent Technologies E5071C (9 kHz to 85GHz) Net-work Analyzer and 3D2D Atenlab Anechoic Chamber Asdepicted in Figure 6 the antenna under test (AUT) performsas a transmitter and a double ridged horn antenna functionsas a receiverThe line of sight (LOS) between the antenna andthe receiver is kept at 30m

3 Results and Discussion

The measurements show that the proposed antenna hassuccessfully achieved aminimum reflection coefficient of lessthan minus10 dB (119878

11lt minus10 dB) With certain R-RFS configura-

tion the return loss of 239GHz is stated atminus184 dBminus183 dBand minus27 dB as shown in Figures 7(a) 7(b) and 7(c) respec-tivelyThose figures indicate that the 90power that has beentransmitted is contributed by proper alignment between theproposed antenna spiral feed line (bottom substrate) and itsradiating elements (top substrate)

A sufficient interelement spacing (IES) of the proposedantenna for three R-RFS arrangements is proven through

International Journal of Antennas and Propagation 5

Proposed antenna

Receiver

(a)

AUT

(b)

Receiver

(c)

Figure 6 Positions of the proposed antenna in the anechoic chamber (a) Point-to-point positioned (b)The proposed antenna (c) Receiver(double ridged horn) antenna

the surface current distribution In Figure 8(a) it is observedthat more inset current has flown to the radiating elementsnumber two and three when R-RFS B and C are ON Lesscurrent has been attracted to the adjacent radiating elementnumber one Figure 8(b) depicts that all radiating elementsfunctioned properly after receiving a number of excitedcurrents from the SMA port Radiating element numbertwo has approximately null current distribution as shown inFigure 8(c) This leads to more current surge in the elementsnumber one and three Generally the presented antenna hasgood antenna isolation and eventually enhanced the radiationefficiency and antenna efficiency to more than 85 and 83respectively

Figures 9 and 10 depict the simulated 3D and measuredradiation pattern of the PIN diode switches configurationIt is realized in both figures that the pattern is radiatedon the 119911-119910 axis at the resonant frequency of 239GHz forWiMAX application The proposed antenna achieved thereconfigurable pattern by controlling the R-RFS switcheswiththe implementation of the spiral feed arm design Spirallingfeed with the rectangular radiating element at the positionof 0∘ 90∘ and 180∘ contributed to the phase shift of the EMwave Moreover the main lobe radiation can be tuned tothe desired direction with certain R-RFS configuration assummarized in Table 1 The high gain measurements andsimulations of the proposed antenna can be attributed to thegood coupling from the feed line to the radiating surfacethrough the appropriate size position and shape of apertureslots The measurements show a very good agreement withsimulations where the radiation patterns are formed suc-cessful with respect to the directional and divisive broadsidebeam characteristics

Figures 10(a) and 10(b) show the measured polar direc-tional radiation pattern with the normalized value As R-RFSB and C are ON the antenna radiation pattern is directed to320∘ with a gain of 335 dBi and HPBW of 69∘ as revealed inFigure 10(a) Figure 10(b) depicts the antenna beam pointedto 35∘ with a gain of 321 dBi and HPBW of 1229∘ whenall R-RFSs are ON Figure 10(c) demonstrates the divisivebroadside radiation pattern headed to 43∘ and 330∘ with again of 280 dBi andHPBWof 703∘ by turningON the R-RFSA and C It is realized that the directional beam has a betterpeak gain of 335 dBi and 321 dBi compared to the broadsidebeam with maximum gain of 280 dBi Based on the resultthe proposed antenna is able to cater for the existence of theWiMAX user between 90∘ and minus90∘ by directing the beam tothe wanted user direction

4 Conclusion

A novel patch array antenna design with directional anddivisive broadside characteristic is proposed The antennaapplied an aperture coupled feed network in order to reducethe signal deterioration due to the implementation of the R-RFS It is discovered that a spiral feed design effectively con-tributed to the achievement of the reconfigurable radiationpattern Through certain R-RFS configuration of the spiralfeed arm the proposed antenna is able to direct its radiatingbeam to the angles of 320∘ or 35∘ and divisive broadside atdirections of 43∘ and 330∘ Therefore the proposed antennawith a wider HPBW can cover the subscriber in the rangebetween minus90∘ to +90∘ For all PIN diode arrangements theantenna well performed at resonant frequency of 239GHz

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

International Journal of Antennas and Propagation 5

Proposed antenna

Receiver

(a)

AUT

(b)

Receiver

(c)

Figure 6 Positions of the proposed antenna in the anechoic chamber (a) Point-to-point positioned (b)The proposed antenna (c) Receiver(double ridged horn) antenna

the surface current distribution In Figure 8(a) it is observedthat more inset current has flown to the radiating elementsnumber two and three when R-RFS B and C are ON Lesscurrent has been attracted to the adjacent radiating elementnumber one Figure 8(b) depicts that all radiating elementsfunctioned properly after receiving a number of excitedcurrents from the SMA port Radiating element numbertwo has approximately null current distribution as shown inFigure 8(c) This leads to more current surge in the elementsnumber one and three Generally the presented antenna hasgood antenna isolation and eventually enhanced the radiationefficiency and antenna efficiency to more than 85 and 83respectively

Figures 9 and 10 depict the simulated 3D and measuredradiation pattern of the PIN diode switches configurationIt is realized in both figures that the pattern is radiatedon the 119911-119910 axis at the resonant frequency of 239GHz forWiMAX application The proposed antenna achieved thereconfigurable pattern by controlling the R-RFS switcheswiththe implementation of the spiral feed arm design Spirallingfeed with the rectangular radiating element at the positionof 0∘ 90∘ and 180∘ contributed to the phase shift of the EMwave Moreover the main lobe radiation can be tuned tothe desired direction with certain R-RFS configuration assummarized in Table 1 The high gain measurements andsimulations of the proposed antenna can be attributed to thegood coupling from the feed line to the radiating surfacethrough the appropriate size position and shape of apertureslots The measurements show a very good agreement withsimulations where the radiation patterns are formed suc-cessful with respect to the directional and divisive broadsidebeam characteristics

Figures 10(a) and 10(b) show the measured polar direc-tional radiation pattern with the normalized value As R-RFSB and C are ON the antenna radiation pattern is directed to320∘ with a gain of 335 dBi and HPBW of 69∘ as revealed inFigure 10(a) Figure 10(b) depicts the antenna beam pointedto 35∘ with a gain of 321 dBi and HPBW of 1229∘ whenall R-RFSs are ON Figure 10(c) demonstrates the divisivebroadside radiation pattern headed to 43∘ and 330∘ with again of 280 dBi andHPBWof 703∘ by turningON the R-RFSA and C It is realized that the directional beam has a betterpeak gain of 335 dBi and 321 dBi compared to the broadsidebeam with maximum gain of 280 dBi Based on the resultthe proposed antenna is able to cater for the existence of theWiMAX user between 90∘ and minus90∘ by directing the beam tothe wanted user direction

4 Conclusion

A novel patch array antenna design with directional anddivisive broadside characteristic is proposed The antennaapplied an aperture coupled feed network in order to reducethe signal deterioration due to the implementation of the R-RFS It is discovered that a spiral feed design effectively con-tributed to the achievement of the reconfigurable radiationpattern Through certain R-RFS configuration of the spiralfeed arm the proposed antenna is able to direct its radiatingbeam to the angles of 320∘ or 35∘ and divisive broadside atdirections of 43∘ and 330∘ Therefore the proposed antennawith a wider HPBW can cover the subscriber in the rangebetween minus90∘ to +90∘ For all PIN diode arrangements theantenna well performed at resonant frequency of 239GHz

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

6 International Journal of Antennas and Propagation

0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(a)

0

minus5

minus10

minus15

minus20

minus25

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(b)0

minus5

minus10

minus15

minus20

minus25

minus30

Refle

ctio

n co

effici

ent (

dB)

2 22 24 26 28 3Frequency (GHz)

SimulationMeasurement

(c)

Figure 7 Measured and simulated reflection coefficient of the proposed antenna (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that was not mentioned is in OFF state

Radiator 1

Radiator 2Radiator 3

(Am)683

64

555

47

384

299

213

128

4270

(a)

(Am)57

535

463

392

321

249

178

107

3560

(b)

(Am)688645

559

473

387

301

215

129

430

(c)

Figure 8 Surface current distributions of the antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c) R-RFS Aand C are ONThe R-RFS that was not mentioned is in OFF state

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

International Journal of Antennas and Propagation 7

(dB)628514

4286171

0571minus307

minus92

minus153

minus215

minus276

minus337

(a)

(dB)554453353252151

0504minus313

minus94

minus157

minus219

minus282

minus345

(b)

(dB)551422328234141

0469minus317

minus95

minus158

minus222

minus285

minus348

(c)

Figure 9 Simulated 3D radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON(c) R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

Measurement

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30

minus30

(a)

Measurement

0

0

30

60

90

120

150180

210

240

270

300

330119910

119911

0

0

0

minus10

minus10minus10

minus10

minus20

minus20minus20

minus20

minus30minus30

(b)

Measurement

030

60

90

120

150180

210

240

270

300

330119910

119911

0

0

minus10

minus10

minus20

minus20

minus30

minus30

minus4000 minus10minus10 minus20minus20 minus30minus30 minus40

(c)

Figure 10 Measured radiation pattern of the proposed antenna at 239GHz (a) R-RFS B and C are ON (b) R-RFS A B and C are ON (c)R-RFS A and C are ONThe R-RFS that not was mentioned is in OFF state

under tolerable 11987811lt minus10 dB On the other hand the antenna

has achieved a compact physical dimension of 100mm by100mm Moreover the proposed antenna radiating elementoccupied a simple shape design yet was able to radiate at apeak gain of 335 dBi The proposed antenna with numerouscompensations has further confirmed its feasibility as aportable IEEE 80216d fixed WiMAX and IEEE 80216emobile WiMAX application A future research of PIN diodecircuit modelling with various inductor and capacitor valuesfor WiMAX application will be investigated

Acknowledgments

The authors acknowledge the contributions of UniversitiMalaysia Perlis (UniMAP) and the Ministry of MalaysianHigher Education (MOHE) for the PhD scholarship ofMuzammil Jusoh which enabled the production of this paperOur gratitude also goes to members of UniMAPrsquos AdvancedCommunication Engineering Centre (ACE) of School Com-puter and Communication Engineering and Wireless Com-munication Centre (WCC) Universiti Teknologi Malaysia

References

[1] C A Balanis Antenna Theory Analysis and Design John Wileyamp Sons 1997

[2] M T Ali M N M Tan T A Rahman M R KamarudinM F Jamlos and R Sauleau ldquoA novel of reconfigurable planarantenna array (RPAA) with beam steering controlrdquo Progress inElectromagnetics Research B no 20 pp 125ndash146 2010

[3] Y Yusuf and X Gong ldquoA low-cost patch antenna phased arraywith analog beam steering using mutual coupling and reactiveloadingrdquo IEEE Antennas and Wireless Propagation Letters vol7 pp 81ndash84 2008

[4] H Fayad and P Record ldquoMulti-feed dielectric resonatorantenna with reconfigurable radiation patternrdquo Progress inElectromagnetics Research vol 76 pp 341ndash356 2007

[5] httpwwwskmmgovmy[6] Y B Jung A V Shishlov and S O Park ldquoCassegrain antenna

with hybrid beam steering scheme for mobile satellite commu-nicationsrdquo IEEE Transactions on Antennas and Propagation vol57 no 5 pp 1367ndash1372 2009

[7] J Ouyang F Yang SW Yang Z PNie andZQ Zhao ldquoAnovelradiation pattern and frequency reconfigurable microstrip

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

8 International Journal of Antennas and Propagation

antenna on a thin substrate for wide-band andwide-angle scan-ning applicationrdquo Progress in Electromagnetics Research Lettersvol 4 pp 167ndash172 2008

[8] G Li S Yang Y Chen and Z Nie ldquoA novel electronic beamsteering technique in time modulated antenna arraysrdquo Progressin Electromagnetics Research vol 97 pp 391ndash405 2009

[9] S V S Nair and M J Ammann ldquoReconfigurable antenna withelevation and azimuth beam switchingrdquo IEEE Antennas andWireless Propagation Letters vol 9 pp 367ndash370 2010

[10] M Jusoh M F Jamlos M F Malek M R Kamarudin and MS Mustafa ldquoA switchable Ultra-wideband (UWB) to tri-bandantenna designrdquo in Proceedings of the Antennas amp PropagationConference Loughborough Loughborough UK November2011

[11] M Jusoh M F Jamlos M R Kamarudin et al ldquoA reconfig-urable Ultra-wideband (UWB) compact tree-design antennasystemrdquo Journal of Progress in Electromagnetic and Research Cvol 30 pp 131ndash145 2012

[12] M A Saed ldquoReconfigurable broadband microstrip antenna fedby a coplanar waveguiderdquo Progress in Electromagnetics Researchvol 55 pp 227ndash239 2005

[13] F Ghanem J R Kelly and P S Hall ldquoSwitched UWB to nar-rowband planar monopole antennardquo in Proceedings of the 4thEuropeanConference onAntennas andPropagation (EuCAP rsquo10)Barcelona Spain April 2010

[14] M F Jamlos O A Aziz T A Rahman et al ldquoA beam steeringradial line slot array (RLSA) antenna with reconfigurableoperating frequencyrdquo Journal of Electromagnetic Waves andApplications vol 24 no 8-9 pp 1079ndash1088 2010

[15] M F Jamlos T A RahmanM R Kamarudin P SaadM AmirShamsudin and A M M Dahlan ldquoA novel adaptive Wi-Fi sys-tem with RFIDrdquo Progress in Electromagnetics Research vol 108pp 417ndash432 2010

[16] M F Jamlos T A Rahman M R Kamarudin P Saad O AAziz and M A Shamsudin ldquoAdaptive beam steering of RLSAantenna with RFID technologyrdquo Progress in ElectromagneticsResearch vol 108 pp 65ndash80 2010

[17] R Garg P Bhartia I Bahl and A Ittipiboon MicrostripAntenna Design Handbook Artech House 2001

[18] httpwwwcstcom[19] httpwwwinfineoncom

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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