A 2.5-D Antenna-Circuit-Antenna Structure-Based Wideband Amplifying Frequency Selective Rasorber

A 2.5-D wideband amplifying frequency selective rasorber (AFSR) is proposed in this paper. First, a 2.5-D antenna-circuit-antenna frequency selective surface (FSS) was suggested. A patch antenna with a U-shaped slot is used for both transmitting and receiving. To provide power amplification, the transmitting and receiving antennas are connected to the power amplifier circuit. On top of AFSS is a lossy layer made up of rectangular spiral resonators and metal wires with resistors. The frequency ranges of the higher absorption band are 7.3 GHz to 9.6 GHz while the lower absorption band is 3.1 GHz to 5.1 GHz. The highest gain of 11.2 dB is achieved with the amplifying passband, which spans from 5.2 GHz to 7.2 GHz.