Characteristic Mode–Enabled Hexagonal Ring Patch Antenna for 5.5 GHz IoT/Wi-Fi Sensing

Mohammed K. Al-Obaidi

doi:10.58564/IJSER.4.4.2025.352

Authors

Mohammed K. Al-Obaidi Al-Iraqia University

DOI:

https://doi.org/10.58564/IJSER.4.4.2025.352

Keywords:

Microstrip antenna, Hexagonal ring, Characteristic Mode Analysis (CMA), WLAN, Modal significance, Bandwidth enhancement, CST Microwave Studio.

Abstract

The design and analysis of a small hexagonal ring microstrip antenna optimized at 5.5 GHz are presented in this work. The FR4 substrate, which has a dielectric constant of 4.3 and a thickness of 1.6 mm, is used to fabricate the antenna because it is inexpensive and compatible with printed circuit board technology. By extending the effective current path and allowing for multiple resonant modes, the hexagonal ring geometry improves radiation performance and impedance bandwidth when compared to traditional rectangular patches. Using CST Microwave Studio, Characteristic Mode Analysis (CMA) is used to analyze the antenna's modal behavior. According to the CMA results, higher-order modes aid in stability, but the dominant resonant mode around 5.5 GHz largely controls the radiation mechanism. With an impedance bandwidth of 126 MHz (5.392–5.518 GHz), the simulated response exhibits a resonance of –20 dB at 5.5 GHz. The antenna produces strong current distribution along the hexagonal edges, broadside radiation, and a steady gain of 6.11 dBi. The design is appropriate for WLAN and Wi-Fi 5 (IEEE 802.11ac) applications because of these features. The hexagonal ring structure is an efficient technique for increasing bandwidth and performance in wireless systems, as demonstrated by the combination of CMA and full-wave simulations.

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