Miniaturized frequency selective rasorber with a X‐band transmission band using cross band resonator

Abstract

This article designs a miniaturized frequency selective absorber (FSR) based on X-band. The FSR consists of a resistor sheet and a bandpass frequency selective surface (FSS). It has a wide low frequency absorption band and a low insertion loss wide high frequency transmission band. The resistor element is a hexagonal metal ring with lumped resistance. Each side of the ring is inserted with three cross metal branches. The branch is equivalent to the λh/4 short-circuit branch. Three types of branches with different lengths can be used to achieve wide-band transmission. The band-pass FSS is a three-layer structure, which is composed of two layers of circular metal patches and a layer of circular aperture. The band-pass FSS must coincide with the transmission band of the resistor sheet. The resistor sheet is placed on the band-pass FSS. At low frequencies, FSR functions as an absorber. The absorption bandwidth of 10 dB is 2.2 to 6.3 GHz. At high frequencies, the transmission band is almost transparent. At this time, the 1 dB transmission bandwidth is 8.1 to 12.1 GHz. FSR has good angular stability and polarization stability. A prototype of the structure was made and measured to verify the correctness of the design.