Design and Development of Inverted U-Slot Rectangular Ring Coupled Monopole Microstrip Antenna for Quad Band Operation

Abstract

This paper present a novel design and development of inverted U-slot rectangular ring coupled monopole microstrip antenna (IURCMMA) for quad band operation. The monopole microstrip antennas are commonly designed for wide band operation. However, by placing the optimum ring slots in the form of slits on the radiating patch, the antenna can be made to operate at different frequency bands. The proposed antenna operates in the frequency range of 1.5 to 10 GHz with a peak gain of 8.69 dB and gives omni directional radiation pattern in both E and H planes. The measured and simulated results of return loss are in good agreement with each other. With these features the proposed antenna may find many applications at microwave frequency range.

Introduction

I. INTRODUCTION

The microstrip antennas have become more popular in the recent years due their light weight, low cost, ease of fabrication, planar and compact.

These antennas are more useful at microwave frequency range usually 1 to 100 GHz. Many researchers have designed microstrip antennas for single, dual, triple and multiband operations at different microwave frequencies. Attempts are made to enhance bandwidth, gain, radiation efficiency etc [1-8]. Notch band microstrip antennas were also designed to avoid unwanted range of frequency in order to stop electromagnetic interference. The researchers have used different geometry, size, materials, techniques to achieve the desired parameters of an antnenna. In this paper a simple method has been used by placing optimum slots in the form of ring slits on the radiating patch, with this the antenna can be made to operate at different frequency bands. This type of study is found to be rare in the literature.

II. GEOMETRY OF IURCMMA

The top and side view geometry of IURCMMA is as shown in Fig 1. The antenna consists of a radiating patch of width Wp and length Lp. A rectangular ring of dimension W2 xL2 is placed at the center of the patch. An inverted U shape coupled ring slot is placed on the patch with a gap of 0.5mm as shown in the figure. The surround patch strip and inner patch acting as parasitic elements to the driven patch. 

The antenna is fed using  a single 50Ω microstripline feed which is connected to 50 Ω SMA connector for excitation. The length of feed is Lf and width is Wf. A partial copper ground plane of height Lg is placed below the microstrip line feed on the bottom layer of the substrate.

The gap between the partial ground plane and radiating patch is g. The antennas is fabricated on low cost glass epoxy dielectric substrate material with a thickness of h and size Ws x Ls having relative permittivity (εr) 4.2 and loss tangent (δ) 0.05. The antenna design model and dimensions have been optimized to achieve quad bands  by using ANSYS HFSS simulation software. The optimized design dimensions of IURCMMA are given in Table 1. The photograph of fabricated antenna is as shown in Fig. 2.

III. RESULTS AND DISCUSSIONS

The Fig 3 shows the variation of return loss versus frequency of IURCMMA. From this figure, it is observed that, the antenna resonates for four bands of frequencies found at fr1 (2.49GHz), fr2 (4.46GHz), fr3 (6.62GHz) and at fr4 (9.55GHz) having minimum return loss of -13.16dB, -30.08dB,-19.87dB and -14.02 dB respectively. The magnitude of bandwidth of each operating band is BW1=35.91% (2.01GHz-2.89GHz), BW2=18.43% (3.94GHz-4.74GHz), BW3=7.77% (6.31Hz- 6.82GHz) and BW4=6.25% (9.30GHz-9.90GHz) with a peak gain of 8.69dB found in its operating band. The experimental variation of return loss versus frequency graph of IURCMMA is in good agreement with simulated graph. The patch and coupled slots make the antenna resonate repetitively due to coupling effect. 

Conclusion

From the detailed experimental and simulation study it is conclude that, the proposed antenna is quite capable for operating four band of frequency in the range of 1.5 to 10 GHz with a peak gain of 8.69 dB. In each operating band the antenna gives nearly omni directional radiation patterns in both E and H plane. The experimental and simulation results of return loss verses frequency is in good agreement with each other. The proposed antenna is simple in its structure and easy to fabricate and use low cost substrate material. With these features the proposed antenna may find many applications at microwave frequencies.

References

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Copyright

Copyright © 2022 Premavani ., C. Kalpana, S. N. Mulgi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.