Tunable pass-band FSS for beam steering applications

In this work we present a tunable pass-band Frequency Selective Surface (FSS) suitable for beam-steering operations. The structure at hand allows to electronically steer the scattered beam by means of a dynamic control of the phase related to the wave transmitted by each unit cell. Such an operation can be performed using electronically tunable capacitances (e.g. varactor diodes or MEMS capacitances) integrated into the passive structure. The proposed technique is capable of a simultaneous control of both the phase and magnitude of the wave transmitted by each cell of the periodic structure. A further improvement to the initial configuration was obtained using a multi-layer arrangement of pass-band FSSs. Full wave simulations and experimental analyses demonstrated a beam-steering FSSs operating within the C-band capable of a maximum control range for the phase of the wave transmitted by each unit cell up to 360° with transmission losses always lower than 3 dB.