Absorptive frequency selective surface with switchable passband

An active absorptive frequency selective surface (AFSS) is proposed in this paper, which is comprised of a switchable bandpass screen and a periodic resistive surface separated by a foam layer. The switchable bandpass screen embedded with PIN diodes achieves the shift of transmission and reflection in the operating band by controlling the bias voltage. The resistive surface consists of several resonance loops inserted with lumped resistors. At the both sides of the operating band, the entire AFSS performs as an absorber with the switchable bandpass screen playing the role of ground plane. The absorption bands range from 1.3 to 6 GHz and 9.5 to 12.5 GHz with a transmission window at 8.2 GHz, which can be removed with little impact on the absorbing properties. A prototype of the structure is fabricated to verify the numerical simulation. Moreover, the simulated results also show that the proposed AFSS exhibits stable performance for different polarized waves due to the symmetric structure.