A Polarization-Insensitive Dual-Transmission Band Frequency Selective Rasorber

Abstract

A polarization-insensitive frequency selective rasorber (FSR) geometry with dual-transmission and dual-absorption band has been presented in this paper. Two passbands appear inside a wide absorption band, thereby resulting in multiple absorption regions surrounding the transmission peaks. The proposed FSR comprises of one absorptive layer and one transmissive layer, separated by an air spacer, and each of them is realized by patterning geometries in a periodic arrangement. The transmission bands are obtained at 5.30 GHz and 8.10 GHz with insertion losses of 0.79 dB and 0.46 dB, respectively. A wide absorption band, originally realized between 2.26 GHz and 8.79 GHz, gets divided into multiple absorption regions due to the presence of in-band transmission peaks and shows two discrete absorption bands from 2.01 GHz to 4.95 GHz and 5.81 GHz to 7.45 GHz. The structure achieves an overall fractional bandwidth of 118.20% with respect to its centre frequency. Polarization-insensitivity as well as angular stability for different polarizations (till 30 angle of incidence) are also observed in the structure. As compared to the existing dual-transmission band rasorber geometries, the proposed FSR offers a simpler design topology, lower footprint, and larger operating bandwidth. Proposed structure has been fabricated and measured to verify proposed design. © 2022 IEEE.