Wide Transmission Band Frequency-Selective Rasorber Based on Convoluted Resonator

This letter proposes a wide transmission band frequency-selective rasorber (FSR) based on a convoluted resonator (CR). The FSR consists of a two-layered metallic structure with an air gap in the middle. At the top layer, the lumped-resistor-loaded metallic dipole with a CR inserted into the center is applied to generate wide absorption and transmission bands. At the bottom layer, the wideband frequency-selective surface is realized by a triple-layer metallic structure, in which two layers of identical square patches are coupled through a layer of the square aperture. The full-wave simulation results show that the wide transmission band with low insertion loss and wide absorption band are realized. To validate the performance of the proposed FSR, the prototypes are fabricated and measured, and reasonable agreement between the simulated and measured results is obtained. The measured results show that the transmission band with insertion loss less than 1 dB is covered from 9.00 to 12.63 GHz with 33.5% relative bandwidth. Compared with the previous FSRs with wide transmission band, the proposed FSR yields the widest relative bandwidth, better oblique performance, and simpler design.