Investigation on the transmission beam-steering capabilities of tunable impedance surfaces

In this work we present a study of active impedance surfaces to be used for beam-steering and beam-forming applications. The intent is to control the shape of the beam scattered by an impedance surface by dynamically controlling the phase of the wave transmitted by each unit cell. Such a control can be obtained embedding an electronically tunable capacitance (e.g. varactor diode or MEMS) into the passive structure. In particular, this paper presents a preliminary study on a varactor-loaded Frequency Selective Surface (FSS) based on rectangular slots. This configuration was analyzed through full wave simulations obtained by tuning the variable capacitances. Results show a wide phase range with an insertion loss of less than 3 dB.