Electronically Controlled Phasing Element for Single-Layer Reconfigurable Reflectarray

An electronically controlled phasing element for a beam-steered single-layer microstrip reflectarray operating at 4 GHz is presented. The phasing element is formed by a printed circular ring equipped with a variable-length arc stub. The reconfigurable design is accomplished by including an open gate p-i-n transistor in the variable-length stub to offer a 1-bit beam-steering ability. Full-wave electromagnetic simulations and measurements are performed to prove the linear phase performance of the proposed cell including the effect of the utilized active chip and its biasing circuit. Those results indicate the high isolation between the phase performance of the utilized cell between the on and off states of the p-i-n switches.