A Polarization-Insensitive Reconfigurable Frequency Selective Surface Switching and Tuning among Absorption, Transmission, and Reflection

Abstract

A polarization-insensitive reconfigurable frequency selective surface (RFSS) exhibiting switching and tuning operations among absorption, transmission, and reflection behaviors has been presented. The unit cell includes a single-layer FR4 substrate with metallic patterns on both sides. The switching and tuning characteristics have been achieved using a set of p-i-n diodes and varactors on the top layer and a set of p-i-n diodes on the bottom layer. The simulation results are observed for four different operating modes, such as OFF (p-i-n diode on the top layer)-OFF (p-i-n diode on the bottom layer), OFF-ON, ON-OFF, ON-ON, and the tuning under each state by regulating the varactor. The results show that the OFF-OFF and ON-OFF provide transmission responses tuning in the range of 2.88-4.36 GHz and 3.0-4.97 GHz, respectively, with corresponding insertion losses of 2.4-3.2 dB and 1.3-3.6 dB. During OFF-ON mode, a narrowband reflection having a reflection coefficient less than -2.5 dB results in the frequency range of 3.21-5.49 GHz. An absorption response is achieved in the ON-ON state with more than 90% absorptivity from 3.28-5.78 GHz. The topology is polarization-insensitive as well as angularly stable. The proposed RFSS satisfactorily performs multifunctional characteristics, thus providing great prospects for various applications. © 2024 IEEE.