A Reconfigurable Reflectarray Antenna in Ka-Band Using Optically Excited Silicon

Reconfigurable reflectarrays provide the ability to combine the advantages of reconfigurable phased arrays with the high gain of reflector antennas. Optical reconfiguration provides the ability to continuously change one or more property of the antenna, without the need for extensive RF biasing compensation. To this end, an optically reconfigurable reflectarray has been designed, operating in Ka-Band. IR-LEDs have been used to activate the Silicon rather than the traditional laser sources. To simulate the reflectarray accurately, the characterisation of Silicon under this type of illumination has been carried out. With these results, the reflectarray was designed from a unit cell approach and simulated. The reflectarray provides gain variation with changes in the optical power intensity. While initial results provide gain intensity variation, it is envisaged that it may be possible to manipulate sidelobes or beam steer using this technique.