High Gain, E-Shaped Microstrip Antenna with Two Identical Slits for 5G Applications in the 60 GHz Band

This article presents a simple, high-gain, E-shaped antenna suitable for 5G applications in the unlicensed 60 GHz band, characterized by high absorption and path losses. In order to optimize the reflection coefficient performance, enhance the gain, and adjust the resonance frequency of the proposed antenna, two identical slits are incorporated into the front edge of the radiating patch. The proposed structure is built on a Rogers RT/Duroid 5880 dielectric substrate, characterized by a thickness of 0.118 mm, a dielectric constant of 2.2, and a tangent loss of 0.0009. The optimized design with a compact size of 3.8 x 6 x 0.118 mm
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achieves an impedance bandwidth (< -10 dB) of 2.135 GHz, extending from 58.876 GHz to 61.011 GHz. As for gain, it changes slightly from 9.17dB at the lower frequency to 9.66dB at the higher frequency and 9.5dB at the center frequency of the operating band. In addition, the antenna achieves nearly consistent radiation efficiency over its operational band, ranging from 87.9% at the highest frequency to 89.2% at the lowest frequency and 88.6% at the center frequency. The design exhibits a good impedance matching between the radiating patch and the feed line, as indicated by the low (VSWR) of 1.01919 and a high return loss of 40.438 dB at the resonance frequency. Although the proposed design has good radiation characteristics, the operating impedance bandwidth covers only a part of the 60 GHz band (57 GHz to 64 GHz), a shortcoming to be overcome in future work. Moreover, design, simulation, and optimization processes are carried out using the CST simulator to ensure that design objectives are met. On the other hand, the HFSS simulator is employed to validate CST simulation results, thus providing a robust validation framework for the antenna design.