Research Article A Suspended Stripline Frequency Tripler ...downloads.hindawi.com/journals/ijap/2015/247537.pdf · Research Article A Suspended Stripline Frequency Tripler Using a

Research ArticleA Suspended Stripline Frequency Tripler Using a Left-HandedNonlinear Transmission Line

In Bok Kim1 Hongjoon Kim2 Hyun Chul Choi2 and Kang Wook Kim2

1LIG Nex1 Co Ltd No 333 Pangyo-ro Bundang-gu Seongnam-si Gyeonggi-do 463-400 Republic of Korea2School of Electronics Engineering Kyungpook National University Sankyuk-dong Buk-gu Daegu 702-701 Republic of Korea

Correspondence should be addressed to Kang Wook Kim kang kimeeknuackr

Received 8 August 2014 Accepted 9 December 2014

Academic Editor Francisco Falcone

Copyright copy 2015 In Bok Kim et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A suspended stripline frequency tripler using a left-handed nonlinear transmission line (LH NLTL) is presented The proposedtripler using the LH NLTL is composed of a series of varactor diodes shunt inductances and a high-pass filter implemented withsuspended stripline (SSL) An ultrawideband microstrip-to-suspended stripline transition is also utilizedThe fabricated LHNLTLprovides the minimum insertion loss of 17 dB and the maximum insertion loss of 47 dB for a wide frequency band from 26 to18GHzAs a tripler themeasuredminimum third harmonic conversion loss is 153 dB at an input frequency of 24GHz and typically17 dB from 2 to 31 GHz

1 Introduction

The frequency multipliers are often used as important com-ponents to obtain low phase noise microwavemillimeter-wave sources High frequency signal sources can be obtainedby multiplying the low frequency signal Generally thefrequency multiplier uses either transistors or diodes as anonlinear element FET multipliers usually have trade-offbetween bandwidth and conversion loss [1] Varactor diodesmultipliers are naturally narrowband [2] However varactordiode-based frequency multipliers in general generate verylittle noise (phase as well as amplitude noises)The only noisesource in this type of multipliers is thermal noise whichcomes from the series resistance of the varactor

Left-handed (LH) media first postulated by Veselago[3] are becoming an exciting reality particularly as theyare being demonstrated in resonant radio frequency andmicrowave circuits [4 5] In [6] the authors presented atheoretical investigation of the basic nonlinear wave prop-agation phenomena in LH media which is based on theduality of the conventional NLTL that is a LH NLTL withanomalous dispersion They also proved theoretically thatthe third harmonic generation could be very effective in LHNLTL The frequency multipliers based on LH NLTLs are

typically compact since the length of the section in practice isdetermined by the diode package size These triplers can alsobe low loss since fewer diodes are required to achieve the samevalue of conversion efficiency The authors in [6] howeverdid not show the actual experimental results In [7 8] theauthors presented the experimental results for the secondharmonic generation in a short LH NLTL Compared to theprevious works [6ndash8] our work shows that the bandwidthof the LH NLTL is extended significantly with an adequatedesign using 3D simulation and careful fabrication anddemonstrates that the third harmonic generation is veryeffective with LH NLTL

In this paper we present a suspended stripline triplerusing a left-handed nonlinear transmission line (LH NLTL)The proposed tripler using the LH NLTL is composed of aseries of varactor diodes shunt inductances and a high-passfilter which were implemented with suspended striplinesCompared to the earlier literature regarding the triplers [9ndash11] our work shows a comparable performance with a smallersize wider bandwidth and a simpler structure And forthe suspended stripline circuit a suitable and high per-forming MS-to-SSL (microstrip line to suspended stripline)transition developed by the authorsrsquo group [12] has beenutilized

Hindawi Publishing CorporationInternational Journal of Antennas and PropagationVolume 2015 Article ID 247537 5 pageshttpdxdoiorg1011552015247537

2 International Journal of Antennas and Propagation

Harmonic generator

(LH NLTL)

High-passfilter

MS-to-SSLtransition

SSL-to-MStransition

In Out

Figure 1 Block diagram of the proposed tripler

Varactor diodes

width line

Top layer

Bottom layer

Unit cell

Side view

65mm06mm

115mm

(a)

Rd RdCL CLLR2 LR2

CR2CR4 CR4LL

(b)

Figure 2 (a) Fabricated third harmonic generator using LH NLTL(b) Equivalent circuit of a unit cell

2 Design of the Balun and Antenna

The proposed tripler is composed of a harmonic generatora high-pass filter and MS-to-SSL transitions as shown inFigure 1 The harmonic generator utilizes nonlinear charac-teristics of the LH NLTL The proposed LH NLTL has asimple structure but provides a wide left-handed passbandTo effectively remove harmonics a suspended stripline 5th-order high-pass filter is added MS-to-SSL transitions areused at the input and output sides to easily integrate withmicrostrip circuits

21 Third Harmonic Generator Design Figure 2(a) shows thepicture of the proposed suspended stripline third harmonicgenerator using six-section LH NLTLs In this paper for thesuspended stripline structures the circuit was realized ona Rogers RO4003 substrate with 120576

119903= 38 thickness ℎ =

03mm and cover height of ℎ119888= 05mmThe fabricated har-

monic generator circuit is 115mm by 65mm in size exceptfor the connectors and extra space for the measurement Arow of 06mm by 14mm copper pads separated by 02mmgaps is formed on the surface of substrateThe twelve varactordiodes (MA-COM MA46H120 hyperabrupt junction GaAsflip-chip) are attached between these pads The junctioncapacitance (119862

1198950) of the diodes from the manufacturerrsquos

data sheet is 11 pF with a capacitance ratio of 119862 (0V)119862(10 V) = 75 The nonlinear capacitance (119862

119871) in each section

is formed by two antiseries diodes Shunt inductances (119871119871)

are implemented with a 06mm wide suspended striplineconnecting the pads to the ground plane The length of theseinductive lines is 57mm The pads on the board surfacetogether with an inherent parasitic effect (119877

119889) introduce

unavoidable series inductance (119871119877) and shunt capacitance

(119862119877) making the whole circuit a composite rightleft-handed

transmission line having an equivalent circuit shown inFigure 2(b)

Figure 3 compares the simulated and measured resultsof the fabricated LH NLTL The simulation was performedwith the CST Microwave Studio Parameters of the equiv-alent circuit model in Figure 2(b) were extracted from the119878-parameters simulated with the Ansys Designer circuitsimulator that is 119862

119871= 11 pF 119871

119871= 18 nH 119862

119877=

04 pF 119871119877= 07 nH and 119877

119889= 21Ohm To enhance

the bandwidth of the left-handed region and to minimizethe parasitic effects various simulations and experimentswere conducted Also the number of LH NLTL sections wascarefully selected through simulations to maximize devicenonlinearity The bandpass type frequency response with aBragg cut-off frequency indicates the left-handed nature ofthe device The LH high-pass cut-off frequency 119891

119888119871and the

RH low-pass cut-off frequency 119891119888119877can be calculated by using

(1) and (2) respectively [13]

119891119888119871= 119891119877

10038161003816100381610038161003816100381610038161003816100381610038161003816

1 minus radic1 +

119891119871

119891119877

10038161003816100381610038161003816100381610038161003816100381610038161003816

(1)

119891119888119877= 119891119877(1 + radic1 +

119891119871

119891119877

) (2)

where 119891119877= 12120587radic119871

119877119862119877 119891119871= 12120587radic119871

119871119862119871

In this paper 119891119888119871

is chosen as 2GHz and 119891119888119877

as 19GHzThe measured frequency bandwidth of the fabricated LHNLTL agrees well with the calculated left-handed passband

22MS-to-SSL Transition Design Wedesigned the LHNLTLand a filter on suspended stripline because the suspendedstripline offers a higher quality factor and wider impedanceranges as compared with other planar transmission lines[13] To combine the advantages of suspended striplineand microstrip line simultaneously a suitable and highperforming transition structure between the two differenttransmission lines developed by the authorsrsquo group wasutilized

Figure 4 shows the picture of the ultrawideband MS-to-SSL transition fabricated in a back-to-back configuration

International Journal of Antennas and Propagation 3

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50

minus10dB cut-off bandwidth26sim180GHz

fcL fcR

Simulated result (S11)Simulated result (S21)

Measured result (S11)Measured result (S21)

Figure 3 Simulated and measured results of the fabricated LHNLTL

Top layer

Bottom layer

Figure 4 Fabricated microstrip-to-suspended stripline transition

The transition is designed to provide broadband impedancematching and smooth field transformation Figure 5 com-pares the simulated and measured results of the transitionIt is observed that the transition has less than 17 dB insertionloss andmore than 10 dB return loss for frequencies fromDCto 20GHz By subtracting the interconnection losses and thetransmission line losses the insertion loss of the implementedtransition is estimated to be less than 05 dB per transition forfrequencies up to 20GHz

23 High-Pass Filter Design Figure 6 shows the picture ofthe fabricated suspended stripline 5th-order high-pass filter[14]The fabricated high-pass filter is 20mm by 3mm in sizeexcept for the connectors and extra space and it has 5th-orderChebyshev response with a 05 dB in-band ripple Figure 7compares the simulated andmeasured results of the proposedfilter The passband is from 55 to 15GHz (3 dB bandwidth)The minimum insertion loss is 02 dB Parameters of theequivalent circuit model were simulated with the AnsysDesigner circuit simulator that is119862

1= 038 pF119862

2= 022 pF

and 119871 = 11 nH

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50



Figure 5 Simulated and measured results of the fabricated transi-tion in a back-to-back configuration with connectors

Top layer

Bottom layer

20mm

3mm

Figure 6 Picture of the fabricated high-pass filter

24 Tripler Measurement Figure 8 shows the picture of theproposed a suspended stripline frequency tripler using six-section LH NLTLs with a high-pass filter The fabricatedtripler is 30mm by 75mm in size except for the connectorsand extra space

Figure 9 shows the conversion loss of the 3rd harmoniccomponent and the suppression levels of the fundamental2nd and 4th harmonics with +25 dBm of input power for thefrequency range from 20GHz to 31 GHz The 3rd harmonicconversion loss ranges from 153 dB to 198 dB at +25 dBmof input power The minimum 3rd harmonic conversion lossis 153 dB when the input frequency is 24GHz The funda-mental frequency suppression level is typically over 50 dBand 2nd and 4th harmonics frequency suppression levelsare typically 30 dBThe decreased 2nd harmonic suppressionover 25 GHz is obtained due to the action of the high-passfilter

Table 1 compares the performance of the proposed triplerwith those in other papers It can be seen that the proposedLH NLTL-based tripler has wider frequency bandwidth andis smaller in size than other triplers reported in the literature


Table 1 A performance comparison of frequency tripler

Title Structure Frequency band[GHz]

Conversion Loss[dB] Size [cm]

[9] LPF + input matching + HBV + output matching + BPF 131sim139 (fo)Pin = 22 dBm 112sim17 2 times 1

Alumina

[10] APDP (anti-parallel pair diode) + BPF 572sim628 (fo)Pin = 22 dBm 166sim185 5 times 2

RT5880

[11] LPF + phase shifters + Schottky diode + BPF 7sim95 (fo)Pin = 22 dBm 17sim20 5 times 2

RO4003

This work varactor diode + stub + HPF 2sim31 (fo)Pin = 25 dBm 153sim198 3 times 07

RO4003

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50



Figure 7 Simulated and measured results of the fabricated high-pass filter

Top layer

Bottom layer

LH NLTLHPF

30mm

75mm

Figure 8 Picture of the fabricated tripler

3 Conclusion

In this paper we present a suspended stripline frequencytripler using a LH NLTL The proposed tripler exhibitsbroader frequency bandwidth in a smaller size with com-parable performance compared with the previously reportedresearch results The fabricated LH NLTL has a wide left-handed passband from 26GHz to 18GHz The measured

70

60

50

40

30

20

10

0

70

60

50

40

30

20

10

0

Con

vers

ion

loss

(dB)

20 22 24 26 28 30

Supp

ress

ion

leve

l (dB

)

Fundamental suppression2nd harmonic suppression

3rd harmonic conversion loss4th harmonic suppression

Input power = 25dBm

Input frequency (GHz)

Figure 9Third harmonic conversion loss and the suppression levelsof the fundamental 2nd and 4th harmonics with +25 dBm of inputpower

third harmonic conversion loss was typically 17 dB at an inputfrequency range from 2GHz to 31 GHz An ultrawidebandmicrostrip-to-suspended stripline transition was used toeasily integrate with microstrip-based circuits

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This work is supported by NRF Korea under Grant no NRF-2012-M1A7A1A02034753

References

[1] A M Pavio S D Bingham R H Halladay and C A SapasheldquoA Distributed broadband monolithic frequency multiplierrdquoin Proceedings of the IEEE MTT-S International MicrowaveSymposium Digest pp 503ndash504 1988


[2] S A Mass and Y Ryu ldquoA broadband planar monolithic resis-tive frequency doublerrdquo in Proceedings of the IEEE Microwaveand Millimeter-Wave Monolithic Circuits Symposium pp 175ndash178 San Diego Calif USA May 1944

[3] V G Veselago ldquoThe electrodynamics of substances with simul-taneously negative values of 120576 and 120583rdquo Soviet Physics Uspekhi vol10 no 4 pp 509ndash514 1968

[4] R A Shelby D R Smith and S Schultz ldquoExperimentalverification of a negative index of refractionrdquo Science vol 292no 5514 pp 77ndash79 2001

[5] A Lai C Caloz and T Itoh ldquoComposite rightleft-handedtransmission line metamaterialsrdquo IEEE Microwave Magazinevol 5 no 3 pp 34ndash50 2004

[6] A B Kozyrev and D W van der Weide ldquoNonlinear wave prop-agation phenomena in left-handed transmission-line mediardquoIEEE Transactions onMicrowaveTheory and Techniques vol 53no 1 pp 238ndash245 2005

[7] A B Kozyrev H Kim A Karbassi and D W van der WeideldquoWave propagation in nonlinear left-handed transmission linemediardquo Applied Physics Letters vol 87 no 12 Article ID 1211092005

[8] H Kim A B Kozyrev A Karbassi and D W van der WeideldquoCompact left-handed transmission line as a linear phase-voltage modulator and efficient harmonic generatorrdquo IEEETransactions on Microwave Theory and Techniques vol 55 no3 pp 571ndash578 2007

[9] K Krishnamurthi E Boch andRGHarrison ldquoAKa-band pla-nar tripler based on a stacked symmetric InP heterostructure-barrier varactorrdquo in Proceedings of the IEEE MTT-S Interna-tional Microwave Symposium Digest vol 2 pp 549ndash552 1995

[10] J Min S Cho H Kim et al ldquoDesign for frequency tripler usingnovel band-pass filter with low insertion lossrdquoThe Journal ofTheKorean Institute of Communication Sciences vol 31 no 10A pp1031ndash1036 2006

[11] C Baer and T Musch ldquoA passive 8 to 24GHz frequency triplerbased on microstrip line circuits and schottky diodesrdquo in Pro-ceedings of the Asia-Pacific Microwave Conference Proceedings(APMC rsquo10) pp 164ndash167 Yokohama Japan December 2010

[12] Y-G Kim and K W Kim ldquoA new design method for ultra-wideband microstrip-to-suspended stripline transitionsrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 801950 9 pages 2013

[13] C Caloz and T Itoh Electromagnetic Metamaterials Transmis-sion Line Theory and Microwave Applications The EngineeringApproach John Wiley amp Sons Hoboken NJ USA 2006

[14] X-J LiaoW-HHsu andM-HHo ldquoDesign of theUWBband-pass filter with a notch response using the suspended striplinerdquoinAsia Pacific Microwave Conference (APMC rsquo09) pp 902ndash904Singapore 2009

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VLSI Design



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Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



Harmonic generator

(LH NLTL)

High-passfilter

MS-to-SSLtransition

SSL-to-MStransition

In Out

Figure 1 Block diagram of the proposed tripler

Varactor diodes

width line

Top layer

Bottom layer

Unit cell

Side view

65mm06mm

115mm

(a)

Rd RdCL CLLR2 LR2

CR2CR4 CR4LL

(b)

Figure 2 (a) Fabricated third harmonic generator using LH NLTL(b) Equivalent circuit of a unit cell

2 Design of the Balun and Antenna

The proposed tripler is composed of a harmonic generatora high-pass filter and MS-to-SSL transitions as shown inFigure 1 The harmonic generator utilizes nonlinear charac-teristics of the LH NLTL The proposed LH NLTL has asimple structure but provides a wide left-handed passbandTo effectively remove harmonics a suspended stripline 5th-order high-pass filter is added MS-to-SSL transitions areused at the input and output sides to easily integrate withmicrostrip circuits

21 Third Harmonic Generator Design Figure 2(a) shows thepicture of the proposed suspended stripline third harmonicgenerator using six-section LH NLTLs In this paper for thesuspended stripline structures the circuit was realized ona Rogers RO4003 substrate with 120576

119903= 38 thickness ℎ =

03mm and cover height of ℎ119888= 05mmThe fabricated har-

monic generator circuit is 115mm by 65mm in size exceptfor the connectors and extra space for the measurement Arow of 06mm by 14mm copper pads separated by 02mmgaps is formed on the surface of substrateThe twelve varactordiodes (MA-COM MA46H120 hyperabrupt junction GaAsflip-chip) are attached between these pads The junctioncapacitance (119862

1198950) of the diodes from the manufacturerrsquos

data sheet is 11 pF with a capacitance ratio of 119862 (0V)119862(10 V) = 75 The nonlinear capacitance (119862

119871) in each section

is formed by two antiseries diodes Shunt inductances (119871119871)

are implemented with a 06mm wide suspended striplineconnecting the pads to the ground plane The length of theseinductive lines is 57mm The pads on the board surfacetogether with an inherent parasitic effect (119877

119889) introduce

unavoidable series inductance (119871119877) and shunt capacitance

(119862119877) making the whole circuit a composite rightleft-handed

transmission line having an equivalent circuit shown inFigure 2(b)

Figure 3 compares the simulated and measured resultsof the fabricated LH NLTL The simulation was performedwith the CST Microwave Studio Parameters of the equiv-alent circuit model in Figure 2(b) were extracted from the119878-parameters simulated with the Ansys Designer circuitsimulator that is 119862

119871= 11 pF 119871

119871= 18 nH 119862

119877=

04 pF 119871119877= 07 nH and 119877

119889= 21Ohm To enhance

the bandwidth of the left-handed region and to minimizethe parasitic effects various simulations and experimentswere conducted Also the number of LH NLTL sections wascarefully selected through simulations to maximize devicenonlinearity The bandpass type frequency response with aBragg cut-off frequency indicates the left-handed nature ofthe device The LH high-pass cut-off frequency 119891

119888119871and the

RH low-pass cut-off frequency 119891119888119877can be calculated by using

(1) and (2) respectively [13]

119891119888119871= 119891119877

10038161003816100381610038161003816100381610038161003816100381610038161003816

1 minus radic1 +

119891119871

119891119877

10038161003816100381610038161003816100381610038161003816100381610038161003816

(1)

119891119888119877= 119891119877(1 + radic1 +

119891119871

119891119877

) (2)

where 119891119877= 12120587radic119871

119877119862119877 119891119871= 12120587radic119871

119871119862119871

In this paper 119891119888119871

is chosen as 2GHz and 119891119888119877

as 19GHzThe measured frequency bandwidth of the fabricated LHNLTL agrees well with the calculated left-handed passband

22MS-to-SSL Transition Design Wedesigned the LHNLTLand a filter on suspended stripline because the suspendedstripline offers a higher quality factor and wider impedanceranges as compared with other planar transmission lines[13] To combine the advantages of suspended striplineand microstrip line simultaneously a suitable and highperforming transition structure between the two differenttransmission lines developed by the authorsrsquo group wasutilized

Figure 4 shows the picture of the ultrawideband MS-to-SSL transition fabricated in a back-to-back configuration


4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50


fcL fcR




Top layer

Bottom layer




1= 038 pF119862

2= 022 pF

and 119871 = 11 nH

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50




Top layer

Bottom layer

20mm

3mm










Alumina


RT5880


RO4003


RO4003

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50




Top layer

Bottom layer

LH NLTLHPF

30mm

75mm


3 Conclusion


70

60

50

40

30

20

10

0

70

60

50

40

30

20

10

0

Con

vers

ion

loss

(dB)

20 22 24 26 28 30

Supp

ress

ion

leve

l (dB

)



Input power = 25dBm






Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50


fcL fcR




Top layer

Bottom layer




1= 038 pF119862

2= 022 pF

and 119871 = 11 nH

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50




Top layer

Bottom layer

20mm

3mm










Alumina


RT5880


RO4003


RO4003

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50




Top layer

Bottom layer

LH NLTLHPF

30mm

75mm


3 Conclusion


70

60

50

40

30

20

10

0

70

60

50

40

30

20

10

0

Con

vers

ion

loss

(dB)

20 22 24 26 28 30

Supp

ress

ion

leve

l (dB

)



Input power = 25dBm






Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation














Alumina


RT5880


RO4003


RO4003

4 8 12 16 20

Mag

nitu

de S

-par

amet

er (d

B)

Frequency (GHz)

0

minus10

minus20

minus30

minus40

minus50




Top layer

Bottom layer

LH NLTLHPF

30mm

75mm


3 Conclusion


70

60

50

40

30

20

10

0

70

60

50

40

30

20

10

0

Con

vers

ion

loss

(dB)

20 22 24 26 28 30

Supp

ress

ion

leve

l (dB

)



Input power = 25dBm






Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article A Suspended Stripline Frequency Tripler ...downloads.hindawi.com/journals/ijap/2015/247537.pdf · Research Article A Suspended Stripline Frequency Tripler Using a