A Miniaturized Frequency Selective Rasorber With Independently Regulated Selective Dual-Transmission Response

Abstract

In this letter, a miniaturized-element dual-polarized frequency selective rasorber (FSR) with independently regulated dual-transmission response has been presented. The proposed FSR is made of two cascaded layers separated by an air spacer, where the top lossy layer provides wideband absorption along with in-band transmission and the bottom lossless layer exhibits a dual bandpass filter. The novelty of the proposed design lies in the use of lumped capacitors in the top layer to realize the independently controlled highly selective transmission frequencies as well as attain a miniaturized unit cell topology (having dimensions of 0.08 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.08 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> , λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> being the lowest operating frequency). In addition, convoluted slot geometries are patterned in the bottom layer to obtain the transmission bands appearing at the same frequencies as that of the top layer. The proposed structure has an operating range of 1.87–7.97 GHz, whereas two distinct transmission responses are located at 3.52 and 5 GHz having insertion losses of 1.2 and 0.82 dB, respectively. Furthermore, the geometry exhibits an angularly stable performance upto 40° for both TE and TM polarizations. A prototype of the proposed FSR was fabricated and measured to validate the simulated responses under normal incidence.