Switchable electromagnetic shield by active frequency selective surface for LTE‐2.1 GHz

In this letter, a simple design method for reconfigurable active frequency selective surface (AFSS) and novel switchable AFSS is presented, which the AFSS can transmit LTE 2.1 GHz signals in PIN‐OFF state while function as a band‐stop filter to shield those signals in PIN‐ON state. Compared with regular square loop AFSS, the proposed structure is exhibited fair stability for different incident angles and much smaller −10 dB bandwidth of | S 21 | for reflection state and reasonable insertion loss for transmission state. By changing DC voltage through bias feeder lines, the switch function can be obviously realized. A prototype is fabricated and measured, and a good agreement between the simulation and measurement results is achieved.