Dual-Polarized Frequency-Selective Rasorber with Switchable Second-Order Bandpass Response

A novel technique is presented for achieving a dual-polarized A-T-A rasorber with a switchable second-order bandpass response. The lossy layer is formed by embedding resonators in a centrally symmetrical manner into the square ring unit. The lossless layer is constructed using a patch-grid coupling structure, thereby enabling the rasorber to exhibit a second-order bandpass response. P-i-n diodes are integrated into the structure, and the symmetric bias design allows for effective control of the passband in dual-polarized scenarios. By toggling the state of the p-i-n diodes, the transparent window in 2.88-3.16 GHz can be triggered, exhibiting sharp roll-off edges. When the window is closed, wideband absorption is achieved in 1.3-4.0 GHz. Details of the proposed reconfigurable rasorber are discussed.