S-band GaAs FET Reconfigurable Reflectarray for Passive Communications

A reflectarray operating at 3.5 GHz is created with individual control of unit element reconfigurability for beamsteering in both azimuth and elevation. The unit element has been co-designed with a gallium arsenide (GaAs) FET on the back side of the reflector to allow the reflected phase to change between 0° and 180°. The phase control can be used to both beamform the reflected signal in a desired direction and modulate data onto a signal of opportunity for short range communications. The simplicity of the unit element and control routing enables the elements to be electrically small (~λ/6 spacing). Over-the-air laboratory measurements indicate the ability to modulate the reflected signal at 10 kbps with a path forward towards higher data rates.