3-D Dual-Polarized Frequency-Selective Rasorber with Wide Absorption Bands and Wide Passband

This paper presents a three-dimensional (3-D) dual-polarized frequency-selective rasorber (FSR), which exhibits two wide absorption bands and a low-insertion-loss wide passband between them. It consists of a 3-D multiple lossy strip-type resonator array and a planar third-order bandpass frequency-selective surface (FSS) as the ground plane. The wideband absorption is achieved by the multi-resonances of the lossy strip-type resonators. The attractive low-insertion-loss wideband transmission is provided by loading the dual-gap ELC resonator in the lossy layer. It is shown that the proposed 3-D FSR exhibits an ultra-wide low-reflection band with a -10dB fractional bandwidth (FBW) of 156% from 2.2 to 18.6GHz, which includes a passband with an FBW of 31.1% from 8.4 to 11.5GHz with an insertion loss of less than 1dB. The equivalent circuit model is established to investigate the operating mechanism. The 3-D FSR prototype is fabricated and measured, and good agreement is observed.