Receiving and Transmitting Antenna Pairs Based Rasorber With High Angular Stability

Frequency selective rasorbers (FSRs) with out-of-band absorption and in-band transmission performance have been widely reported for stealth radome applications over the past few years. However, developing an FSR with high angular stability in the transmission band remains challenging. Therefore, to improve the transmission angular stability, we propose an innovative architecture in this work for constructing the FSR with independently explorable absorption and transmission paths. First, a band-stop frequency selective surface (FSS) and an absorber are employed in the absorption path to obtain out-of-band absorption. Second, the receiving (RX) and transmitting (TX) antenna pairs connected by the corresponding enclosed transmission lines (TLs) are utilized to comprise the transmission path. Note that a wide-beam RX antenna is employed to capture incident electromagnetic (EM) waves at large angles and achieve in-band transmission with high angular stability. Besides, another second-order FSR with a sharp roll-off transmission filtering response is proposed by using the second-order band-stop FSS as the ground (GND) of the RX antenna. Furthermore, two prototypes of the FSRs (one narrowband and the other second-order) are fabricated and measured as demonstrations of the proposed architecture. Experimental results agree with simulation ones, indicating the two devices exhibit the −3-dB transmission bands with excellent angular stability of 60°, and both transmission windows are located on a wide −10-dB low reflection band.