A Polarization-Insensitive Dual-Band FSS With High Selectivity and Independently Switchable Characteristics

The investigation of dual-band frequency selective surface (FSS) has attracted a great deal of attention over the past few decades. However, the existing reconfigurable dual-band FSSs exhibit first-order responses with poor frequency selectivity. In this letter, a polarization-insensitive dual-band FSS with a rotationally symmetrical receiver–transmitter unit-cell configuration that exhibits a second-order response is presented. p-i-n diodes are loaded on separate layers to achieve the independent switching of two passbands. The full-wave simulation results are presented, and an equivalent circuits model is also presented to analyze the operation principle of the proposed FSS. The measurement results of our fabricated prototype indicate that the device exhibits two independently switchable polarization-insensitive transmission bands centered at 3.06 and 4.33 GHz. The shape factors representing the selectivity of the transmission band are 2.44 and 2.46, respectively, which are approximately 1/4–1/2 times that of the existing reconfigurable dual-band FSSs. The proposed FSS exhibits angular stability up to 40
$^{\circ }$
below 5 GHz. This work paves the way toward high selectivity reconfigurable dual-band FSS.