Design and Analysis of a Plasma-Based Reconfigurable and Frequency-Selective Rasorber

A frequency-selective absorber (FSA), also known as a rasorber, is a specialized structure designed to absorb a wide range of the electromagnetic (EM) spectrum while selectively allowing specific frequencies to either reflect or transmit through it. An FSR with wide absorption performance and a transmission band has many applications, including the multi-station Radar cross section (RCS) enhancement problem beyond the antenna working region. However, achieving a wideband absorption FSR with a narrow transmission band and low insertion loss is very challenging.

This study focuses on investigating a frequency-selective absorber that exhibits a nearly transparent window between two absorption bands. The rasorber structure comprises a resistive sheet and a bandpass frequency-selective surface (FSS) with an air gap positioned in between. Gas discharge tubes (GDTs) have been employed as plasma cells to achieve parallel resonance within the resistive element. This unique configuration enables the rasorber to be reconfigured when incoming high-power microwave signals ignite the plasmas within the system. Additionally, the structure's bottom layer is optimized to align with the transmission band of the resistive sheet, ensuring efficient performance. Simulated results demonstrate the successful implementation of this technique. The forthcoming discussion will delve into the fabrication details and provide experimental findings to complement the study.