Metasurface Instrumented High Gain and Low RCS X-Band Circularly Polarized MIMO Antenna for IoT Over Satellite Application

Abstract

In this article, a UWB metasurface absorber is designed for a frequency range of 6.75GHz-14.5GHz. The absorber consists of a simple unit cell size of 0.265λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.265λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.103λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> on a single-layer FR-4 substrate with a thickness of 3.1mm. It has greater than 90.0% absorbance. Next, an X-band circularly polarized MIMO antenna is developed on an FR-4 substrate with a thickness of 1.0mm. The antenna has dimensions of 0.966λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.766λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.053λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . The MIMO antenna’s S-parameters, radiating efficiency, gain, and diversity parameters are further indicators of its usefulness. The designed metasurface is also employed as a tool to enhance the peak gain of the proposed MIMO antenna up to 8.8dBi and reduce radar cross-section by 18dBm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , by placing the metasurface array superstrate and down correspondingly. The simulated and measured results for the metasurface and antenna, both individually and collectively, are more harmonious, demonstrating the applicability of the suggested designs for IoT over satellite, military applications, and identifying blood clots in CT-scan applications.