Design and Analysis of Rectangular Circularly Polarized Array Antenna for Flexible IoT Applications

In this work, a Coaxial fed 2 × 2 array antenna is proposed. This antenna employsfour patch elements, and the individual feedlines are connected to a standard coaxial feed. The size of the antenna is 74.4 × 74.4 mm2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathrm{mm}}^{2}$$\end{document} with a substrate thickness of 1.6 mm. Polyamide is used as a substrate which has a dielectric constant of 4.3. The antenna's operating band starts from 4.05 to 4.32 GHz, with a bandwidth of 0.27 GHz and a resonating frequency of 4.2 GHz and 5.2 GHz. The proposed antenna achieved a peak gain of 9.1 dB and a radiation efficiency of 85%. The design and simulations of the antenna were made using HFSS software. This antenna works for receiving band of standard c-band and as radio altimeters.