High Permittivity Design of Rectangular and Cylindrical ...onlinepresent.org/proceedings/vol147_2017/5.pdf · Cylindrical Dielectric Resonator Antenna for C ... 7.39 GHz simulated

High Permittivity Design of Rectangular and

Cylindrical Dielectric Resonator Antenna for C-Band

Applications

Dr.K.Srinivasa Naik1, Darimisetti Sai Kiran1 and Dr.S.Aruna2

1,2Department of Electronics and Communication Engineering, 1Vignan’s Institute of Information and Technology, Visakhapatnam, A.P, India

[email protected] 2Andhra University College of Engineering, Visakhapatnam, A.P, India

[email protected]

Abstract. A High permittivity design of Rectangular and Cylindrical dielectric

resonator antennas is modeled for C-band applications. The collusion consists

of a Rectangular and Cylindrical DRAs with a dielectric constant ε_r of

34(Dibarium nona titanate) excited by a T shaped microstrip feed line. The

constructed antenna is placed on a ground plane with a size of 50 × 50 × 0.035

mm3. The proposed DRAs offers a high gain of 10 dB around the center

frequency 4.79 GHz in RDRA and 5 dB gain in CDRA around the center

frequency 7.46 GHz simulated by using Ansys HFSS Electromagnetic

Suite18.1 and gain of 5.03 around the center frequency 4.57 GHz and 4.71 dB

gain in CDRA around the center frequency 7.39 GHz simulated by using CST

Studio Suite 2017.

Keywords: Dielectric resonator antennas (DRAs), Microstrip line feed, Ansys

HFSS Electromagnetic Suite and CST Studio Suite

1 Introduction

DRAs are mostly used in the microwave and millimeter wave communications for

their several applications and they are having dielectric constant ranging from 10 to

100 which are mainly suitable in antenna designing applications [1]. These DRAs

were proposed by Robert Richtmyer in 1939 and later on developed by S. A. Long in

1983.In DRA design, the implementation of the DRA geometry and various relative

permittivity’s can provide different simulation results [5].

Predominantly, DRAs can be initiated through a microstrip feed line to provide

better bandwidth [6] and linearly polarized radiation characteristics and easier to

fabricate the prototype design [3]. For designing the DRAs, the dimensions and

dielectric constant of the resonator are chosen to function properly. By DRAs, we can

avoid surface wave losses to increase the bandwidth, better polarization over than the

microstrip patch antennas [11].

The DRAs can be designed easily for suitable applications in the required band of

frequency. The Proposed work is used for many wireless communications, satellite

communications, radar systems [10] and UWB Applications. The proposed antenna

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017), pp.34-41

http://dx.doi.org/10.14257/astl.2017.147.05

ISSN: 2287-1233 ASTL Copyright © 2017 SERSC

aims at providing applications for C-band [8]. The methods to improve the

performance of DRAs by optimizing excitation techniques, presenting an air gap

between the resonator and ground plane, modifying the resonator shapes and altering

the different dielectric constants of the DRAs. Usually DRAs gives low gain value,

but to get higher directivity and gain values, arrays of dielectric resonator are to be

used.

Cylindrical DRA involves a cylindrical shaped dielectric resonator (DR) with a

height Hc, radius RC, and dielectric constant εr . The DR is etched on a ground plinth

surface and fed by a microstrip line feed. Ease of fabrication and the ability to

generate different modes in cylindrical DRA [2] and Rectangular DRA consists of a

rectangular shaped dielectric resonator DR with a dielectric constant εr . The

dimensions of the rectangular DRA are width Wr ,length Lr and height Hr are etched

on a designed plinth with a microstrip line feed and it gives more flexibility in design

as compared to the cylindrical DRA and it is characterized by low cross-polarization

level as compared to the cylindrical DRA [4].

(a) (b)

Fig. 1. Coordinate arrangement of the proposed DRAs: (a) Top view of RDRA (b) Top view of

CDRA

DRAs are used in high range frequency applications due to a property of low

metallic conductor losses [12]. Antenna characteristics having an impact on dielectric

material properties of dielectric constant values and loss tangents. In this proposed

work, Dibarium nona titanate used as a ceramic material with ferroelectric, piezo

electric and pyro electric properties. These crystals are used in capacitors,

electromechanical transducers and nonlinear optics.

In this proposed work, geometry of rectangular and cylindrical dielectric resonator

antenna is designed, optimized and analyzed by using simulation software like Ansys

HFSS and CST Studio Suite to get antenna parametric results like return loss, VSWR,

Directivity and Gain values [13].

Advanced Science and Technology Letters Vol.147 (SMART DSC-2017)

Copyright © 2017 SERSC 35

2 DRA Design Considerations

The coordinate arrangement of the proposed DRAs is constructed in Fig. 1. The

antennas are incorporated with rectangular and cylindrical DRA fed by a T shaped

microstrip line feed which is supported by a 50×50×1.6 mm3 substrate with relative

permittivity of 𝜀𝑠= 4.4 of material FR-4 Epoxy. The RDRA with relative permittivity

𝜀𝑟 = 34 and loss tangent tan δ = 0.002 has a dimensions of length 𝐿𝑟 = 11.95 mm,

width 𝑊𝑟 = 22.5 mm, and a height 𝐻𝑟 = 5.55 mm respectively and CDRA has radius

𝑅𝑐 = 9 mm and Height 𝐻𝑐 = 6mm with relative permittivity 𝜀𝑟 = 34 and loss tangent

tan δ = 0.002. A PEC conductor with a size of 50 × 50 × 0.035 mm3 is applied on the

bottom plane of the FR-4 Epoxy substrate. Designed antenna has been acted through

analysis for operations in C-band frequency range with the dimensions are aligned in

below Table 1.

Table 1. Dimensions of the Proposed Antennas

Parameters Value/Dimension

(mm)

Parameters Value/Dimension

(mm)

εr 34 LS 50 mm

Wr 11.9 mm Hs 1.6 mm

Lr 22.5 mm Wg 50 mm

Hr 5.55 mm Lg 50 mm

RC 9 mm Hg 0.035 mm

Hc 6 mm Lf1 = Lf2 15 mm

Ws 50 mm Wf1 = Wf2 3 mm

3 Numerical Analysis

The lowest order mode TE111 field equations are used to design the RDRA structural

dimensions to get theoretical resonant frequency of the desired dominant mode which

are presented below in the equation (1).

𝑘𝑧tan(𝑘𝑧𝑑/2) = √(𝜀𝑟 − 1)𝑘02 + 𝑘𝑧

2 (1)

Where, 𝑘𝑥2 + 𝑘𝑦

2 + 𝑘𝑧2 = 𝜀𝑟𝑘0

2

and 𝑘0 = 2𝜋𝑓0, 𝑘𝑥 =𝑚𝜋

𝑊𝑟, 𝑘𝑦 =

𝑛𝜋

𝐿𝑟, 𝑘𝑧 =

𝑝𝜋

2𝐻𝑟

Where, 𝑓0 is the operating frequency and𝑊𝑟, 𝐿𝑟, 𝐻𝑟 represents the Width, Length

and Height of the rectangular dielectric resonator antenna respectively.

The CDRA structural dimensions are represented below to get resonant frequency

[7] in the equation (2).

𝑓𝑟 = (2.208 × 𝑐

2𝜋𝐻𝑐√𝜀𝑟 + 1)[1 + 0.7013(

𝑅𝑐

𝐻𝑐) − 0.002718(

𝑅𝑐

𝐻𝑐) 2] (2)


36 Copyright © 2017 SERSC

Where, 𝑓𝑟 -Resonant frequency

c - Velocity of light = 3 × 108m/sec

𝑅𝑐 -Radius of the CDRA

𝐻𝑐 -Height of the CDRA.

These dielectric resonators are excited by a T shaped microstrip feed line to

allocate wider bandwidth and better radiation patterns [9].

4 Simulated Results

In these DR antennas, the transmitted signal reflected energy is find through the

Return Loss (impedance bandwidth S11) as shown in the figures 2-5, VSWR ratio is

nothing but power reflected from the antenna, those results are shown in the figures 6-

9, and Gain plots are shown in the figures 10-13.

A. Return Loss

Fig. 2. Return Loss of RDRA using HFSS

Fig. 3. Return Loss of CDRA using HFSS



Fig. 4. Return Loss of RDRA using CST

Fig. 5. Return Loss of CDRA using CST

B. VSWR

Fig. 6. VSWR plot of RDRA using HFSS

Fig. 7. VSWR plot of CDRA using HFSS



Fig. 8. VSWR plot of RDRA using CST

Fig. 9. VSWR plot of CDRA using CST

C. Gain

Fig. 10. Gain plot of RDRA using HFSS

Fig. 11. Fig 11. Gain plot of CDRA using HFSS



Fig. 12. Gain plot of RDRA using CST

Fig. 13. Gain plot of CDRA using CST

Table 2. Performance comparison of the proposed DRAs between Antenna Parameters

Parameters HFSS CST

RDRA CDRA RDRA CDRA

Dielectric Constant 34 34 34 34

Resonating

Frequency 4.79 GHz 7.46 GHz 4.57 GHz 7.39 GHz

S11 -35.81dB -26.93dB -17.90dB -19.44dB

VSWR 1.03 1.09 1.31 1.23

Directivity 10 dBi 5 dBi 5.13 dBi 5.75 dBi

Gain 10 dBi 5 dBi 5.02 dBi 4.70 dBi

The above Table 2 shows the performance comparison of the proposed DRAs

between Antenna Parameters.



5 Conclusion

The design of Rectangular and Cylindrical dielectric resonator antenna using T

shaped microstrip feed line has been proposed. The presented DRAs will works in the

range of 4-8 GHz frequency and a multi band configuration is presented in these

DRAs. It consists of a rectangular and cylindrical DRAs excited by T shaped

microstrip feed line. The proposed DRAs have a potential to work in wideband

applications operating at C-band. As per the proposed design, HFSS results will give

better than CST based results and RDRA gives best results than CDRA. By designing

arrays and by altering the feed mechanisms through this DRAs, Directivity and Gain

factor will increases.

References

1. Richtmyer, R. D., Dielectric resonators," J. App. Phy., Vol.10,391-398, Jun.1939.

2. S. A. Long, M.W. McAllister, and L. C. Shen, “The resonant cylindrical dielectric cavity

antenna,” IEEE Trans. Antennas Propagat., vol. AP-31, pp.406–412, May1983.

3. Petosa, Dielectric Resonator Antenna Handbook, Norwood: Artech House Inc., 2007.

4. R. K. Mongia and A. Ittipiboon, “Theoretical and experimental investigations on

rectangular dielectric resonator antennas,” IEEE Trans.Antennas Propag., vol. 45, no. 9,

pp. 1348–1356, Sep. 1997.

A. Petosa and S. Thirakoune, “Rectangular dielectric resonator antennas with enhanced gain,”

IEEE Trans. Antennas Propag., vol. 59, no. 4, pp. 1385-1389, Apr. 2011.

5. Saed, M. and R. Yadla, “Microstrip-fed low profile and compact dielectric resonator

antennas,” Progress In Electromagnetics Research, PIER 56, 151–162, 2006.

6. De Young, C. S. and S. A. Long, “Wideband cylindrical and rectangular dielectric

resonator antennas,” IEEE Antennas and Wireless Propagation Letters, Vol. 5, No. 1, 426–

429, 2006.

7. Rezaei, P., M. Hakkak, and K. Forooraghi, “Dielectric resonator antenna for wireless LAN

applications,” IEEE Antennas and Propagation Society International Symposium, Vol. 2,

1005–1008, July 2006.

8. K. P. Esselle, “A low-profile rectangular dielectric resonator antenna, IEEE Trans.

Antennas Propagat., vol. 44, no. 9, pp. 1296-1297, 1996.



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High Permittivity Design of Rectangular and Cylindrical ...onlinepresent.org/proceedings/vol147_2017/5.pdf · Cylindrical Dielectric Resonator Antenna for C ... 7.39 GHz simulated