Design of an electronically beam scanning reflectarray using aperture-coupled elements

The design of a C-band electronically beam scanning reflectarray is presented. The reconfigurable reflectarray element consists of a microstrip patch, printed on a flexible membrane substrate, aperture-coupled to a transmission line loaded with two varactor diodes. The designed element allows continuous tuning of the reflected signal's phase over a 360[degrees] range with a maximum loss of 2.4 dB at 5.4 GHz. The measured results on a 30-element reflectarray breadboard show that by varying the bias voltages on each element the main beam can be steered to large angles, up to 40[degrees] from broadside in the H-plane. A loss analysis of the proposed reflectarray is also presented. Index Terms--Antenna arrays, microstrip antennas, reflectarray antennas, scanning antennas.