A Compass Shaped Microstrip Patch Antenna with Angular Analytics in the UWB Region

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A Compass Shaped Microstrip Patch Antenna with Angular Analytics in the UWB Region

1^st Bandhakavi. S Deepak Department of Electrical Engineering

National Institute of Technology Rourkela, India

2^nd Konidala R. Subhashini Department of Electrical Engineering

National Institute of Technology Rourkela, India

Abstract—Proposed is a novel microstrip patch antenna design and analysis, where a compass shaped radiating element is placed on FR4 substrate with defected ground structure. The design has been carried out in the High Frequency Structure Simulator (HFSS) software in the perspective of angular analytics, pinpointing the significance of positioning the microstrip radiator in diverse angles reflecting on the operating bands of frequencies, gains, and their respective current distributions.

The entire analysis has been carried out in the UWB region considering the threshold of S11 ≤ −10dB and the analytics w.r.t various parameters have been tabulated. The simulated and the experimental results are in good accordance with each other.

Index Terms—Compass Shaped Radiating Element, Angular Position, UWB, Gain and Bandwidth.

I. INTRODUCTION

A simple microstrip patch antenna having versatility w.r.t the operating frequency bands and bandwidths is worthwhile.

In fact, customizing the operating frequency bands or bandwidths without much compromise in the gain and other vital parameters is commendable. Wideband antennas have grabbed lot of attention for the modern era communications and to achieve those wide bandwidths, the preferred choices would be fractal antennas or antenna arrays depending on the demand of the application/s. Certain geometrical shapes have got peculiar radiation characteristics despite not falling under the fractal geometries. The literature related to such geometrical shaped microstrip patch antennas is creeping up in numbers. A few of them which are touch similar w.r.t the operating band of frequencies are presented as follows. Tonmoy K. Saha proposed a compact, pentagon slotted circular monopole antenna with defected ground structure (DGS) for ultra-wideband applications with a peak gain of 2.8 dB. Emre Kurtulan experimented on a circular bridged microstrip patch antenna for wireless applications and analysed that, the antenna covers a bandwidth of 9.59 GHz (i.e., from 4.96 to 14.55 GHz) with a peak gain of 4.81dB.

Deeplaxmi V. Niture presented a simple printed reconfig- urable antenna which can switch between UWB and two other narrow bands (3.1 and 8.23 GHz respectively) for cognitive radio application with a maximum observed gain of 2.8 dBi.

[4] M. M. Hasan Mahfuz reported on a rectangular patch antenna design with DGS operating from 2.7 to 13 GHz with

a semi-circular slot on the radiating element to reject the band from 3.25 to 3.8 GHz. The rejection bands and bandwidths can be altered by changing the width of the patch. [5] Prashant Babbar examined the characteristics of a simple square patch antenna for UWB applications (operating in between 3.8 and 11.8 GHz) with a couple of notch bands at 5.5 and 7.5 GHz due to C-shaped and inverted Pi shaped etches respectively.

The proposed antenna design is much simpler than the ones that are discussed so far, and the investigation is towards the switch in frequency bands, bandwidths and/or resulting changes in the gains, as well as the surface current distributions depending on the angular position of the compass pointer (i.e., the extended radiating element to the circular patch). Prior to fabrication, the angular position of the compass pointer blended to the circular patch can be identified based on the demand of the application in the UWB region and shall be customized. Detailed analyses of the proposed antenna design along with the simulation results are incorporated in the following sections.

Fig. 1. Iteration wise Design of the Proposed Antenna (a) Circular patch with full ground plane, (b) Circular patch with truncated ground plane, (c) Circular patch with defected ground structure (DGS) & (d) Proposed antenna with compass shaped radiating element.

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II. ANTENNADESIGN

A compass pointer shaped microstrip patch as a radiating element placed on FR4 substrate (εr = 4.4) of dimensions 45×40×1.6mm³with defected ground structure is designed in HFSS simulation software. The developments in the design are as shown in “Fig. 1”, and all the details of design parameters and their dimensions including patch, substrate and ground plane are displayed in Table I. The major focus here in the proposed model is to explore the possible variations in the return loss, operating bands of frequencies, bandwidths, gains and current distributions when the compass pointer is inclined at distinct angles.

The design of the proposed model is extracted from a simple circular patch monopole antenna with full ground plane in stages by truncating it to an optimal level, followed by opening a V-groove on the ground plane just below the circular patch, along the axis of feedline as depicted in the “Fig. 1(c)”. Later, a compass pointer shaped patch (combination of a hexagon and a triangle) is blended to the circular patch (dimensions of the compass pointer are mentioned in Table I in correlation with “Fig. 1(d)”). The angular analysis has been carried out based on the inclination made by the compass pointer w.r.t the axis of the feedline.

TABLE I

OPTIMALDESIGNPARAMETERS OF THEPROPOSEDANTENNA. Description of Value Description of Value

Parameter (mm) Parameter (mm)

Length of the 45 Height of the Compass 12 Substrate (Ls) Pointer from the

Circular Patch (Hcp) Width of the 40 Width of the Hexagon 8

Substrate (Ws) in the Compass

Pointer (Wh)

Length of the 19 Nib Height of the 5

Defected Ground Compass Pointer (Hn) Plane (Ldgp)

Width of Ground 40 Length of the 19.5

Plane (Wgp) feed line (Lf l)

Depth of V-groove 7 Width of the 4

in the DGS (Dvg) feed line (Wf l)

Radius of the 6 Height of the 1.6

Circular Patch (a) Substrate (h)

III. RESULTS ANDDISCUSSION

An experimentation done by inclining the compass shaped patch w.r.t feedline axis has been evaluated in terms of operational bands (bandwidths), resonating frequencies and respective maximum gains at resonant frequencies as presented in Table II. The noticeable facts here are the bandwidth improvements identified in the operating frequency bands and their peak gains. When the antenna is operated with 0^◦ inclination the bandwidths of the operating bands in the UWB region are recorded as 0.83 GHz and 2.76 GHz respectively with a peak gain of 4.21 dB at 6.15 GHz. When induced an inclination of 30^◦, the bandwidths of the operating bands in the same UWB have changed to 0.72 GHz and 4.59 GHz respectively leading to a bandwidth enhancement of 166%, and

TABLE II

COMPASSPOINTERANGULARPOSITIONANALYTICS W.R.T OPERATIONALBANDS, RESONATINGFREQUENCIES,AND THEIR

RESPECTIVEMAXIMUMGAINS.

Angular Position Operational Resonating Maximum Gains of the Compass Bands Frequencies of Resonating w.r.t the Axis of (GHz) (GHz) Frequencies

the Feed Line Respectively (dB)

0^◦ 2.33 to 3.16 & 2.57, 6.15 & 2.42, 4.21 &

5.67 to 8.43 7.78 3.69

30^◦ 2.36 to 3.08 & 2.59, 6.15 & 2.36, 4.94 &

3.95 to 8.54 7.71 5.23

45^◦ 2.39 to 3.05 & 2.61, 6.33 & 2.35, 4.56 &

3.91 to 10.81 7.50 5.03

60^◦ 2.43 to 3.01, 2.65, 4.81 & 2.22, 2.90 &

3.91 to 8.21 & 7.31 4.95

8.8 to 11

90^◦ 4.02 to 8.03 & 4.71, 7.34 & 2.54, 4.69 &

9.26 to 11 9.98 5.42

Fig. 2. (a) Iteration wise return loss parameter (b) S11 plot of various angular positions of compass pointer w.r.t axis of the feedline.

the peak gain achieved is 5.23 dB at 7.71 GHz. Similarly, when the inclination is made as45^◦, the bandwidth is improved by 250% with 5.03 dB as the peak gain at 7.5 GHz. For 60^◦ inclination case, although the % bandwidth improvement is

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Fig. 3. Surface current densities at the compass pointer angular positions (a) 0^◦, (b)30^◦, (c)45^◦, (d)60^◦, & (e)90^◦w.r.t axis of the feedline at 6.5 GHz frequency.

Fig. 4. Radiation patterns of0^◦inclined compass pointer at (a) 2.57, (b) 6.15

& (c) 7.78 GHz frequencies.

relatively less, there is a third operating band that has come into the picture. Even the 90^◦ inclination case contributes towards the improvement in the bandwidth, as well as the peak gain.

Fig. 5. Radiation patterns of30^◦ inclined compass pointer at (a) 2.59, (b) 6.15 & (c) 7.71 GHz frequencies.

Fig. 6. Radiation patterns of45^◦ inclined compass pointer at (a) 2.61, (b) 6.33 & (c) 7.50 GHz frequencies.

Iteration wise and compass angular position wise return loss characteristics are embedded in “Fig. 2(a)”and “Fig. 2(b)”

respectively. The dynamics of surface current densities observed at distinguished angular positions of the compass

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Fig. 7. Radiation patterns of60^◦inclined compass pointer at (a) 2.65, (b) 4.81 & (c) 7.31 GHz frequencies.

Fig. 8. Radiation patterns of90^◦inclined compass pointer at (a) 4.71, (b) 7.34 & (c) 9.98 GHz frequencies.

shaped radiator are furnished in “Fig. 3(a-e)”. “Fig. 4” to

“Fig. 8”represents the radiation patterns of all the foremen- tioned angular positions of the compass.

The fabricated model of the proposed antenna (with 0^◦ inclination) and its experimental results are as shown in

“Fig. 9” and “Fig. 10” respectively.

Fig. 9. Fabricated model of the proposed antenna design (with0^◦inclination)

Fig. 10. Experimental results (S11) of the proposed antenna design (with0^◦ inclination)

IV. CONCLUSION

A novel solution in terms of a simple compass shaped microstrip patch antenna with defected ground structure is designed for achieving improved bandwidths and enhancements in peak gains by inducing inclinations to the extended patch in the form of compass pointer attached to the circular microstrip patch antenna. The results have showcased the improvements.

REFERENCES

[1] Tonmoy K. Saha, Carlene Goodbody, Tutku Karacolak, Praveen K.

Sekhar, “A compact monopole antenna for ultra-wideband applications”, Microwave & Optical Technology Letters, 61:182–186, 2019.

[2] Emre Kurtulan , Vinita Mathur, Parul Tyagi, Neha Singh, “Bridged Circular Microstrip Patch Antenna for Wireless Applications”, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2021.02, (2021).

[3] Deeplaxmi V. Niture, Santosh S. Jadhav, S. P. Mahajan, “Recon UWB Antenna for Cognitive Radio”, Progress In Electromagnetics Research C, Vol. 79, 79–88, 2017.

[4] M. M. Hasan Mahfuz, Md Mohiuddin Soliman, Md Rafiqul Islam,

“Design of UWB Microstrip Patch Antenna with Variable Band Notched Characteristic for Wi-MAX Application”, IEEE Student Conference on Research and Development (SCOReD) 27-28 September 2020, Johor, Malaysia.

[5] Prashant Babbar, Ushaben Keshwala, “Design of dual band-notch square patch antenna for UWB applications”, 7th International Conference on Signal Processing and Integrated Networks (SPIN), 2020.

[7] N. Sudhakar Reddy, et al., “Performance and design of spear shaped antenna for UWB band Applications”, Alexandria Engineering Journal, 2017.

[8] Said E. El-Khamy, Amira Zaki, Salah Hamdy, Ahmed El-Khouly, “A new fractal-like tree structure of circular patch antennas for UWB and 5G multi-band applications”, Microwave & Optical Technology Letters, Volume59, Issue9, Pages 2168-2174, 2017.

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[9] Aliakbar Dastranj, Fatemeh Ranjbar, and Mosayeb Bornapour, “A New Compact Circular Shape Fractal Antenna for Broadband Wireless Com- munication Applications”, Progress In Electromagnetics Research C, Vol. 93, 19–28, 2019.