Frequency-Selective Surface with Wide-range Tunable Passband

A reconfigurable frequency selective surface (RFSS) whose passband can be tuned in wide band is presented in this paper. An equivalent circuit model that consists of parallel and series L-C resonant circuits is studied. The unit cell of the FSS is designed with cross-loop slot and varactor diodes which are used to vary the center frequency of the passband. The simulated results show that a tunable passband alters from 2.93 to 5.75 GHz is achieved if the value of capacitance varied from 0.8 to 0.1 pF. The proposed RFSS is manufactured and tested after it is designed. The measured results show that, if the biasing voltage of all varactor diodes is decreased from 18 to 4V, the center frequency of the passband is altered from 4.67 to 2.93 GHz.