Experiments on an Optically Controlled 2-D Scanning Antenna 1

We present latest results on an optically-controlled, millimeter wave (MMW) scanning antenna. The antenna employs a photo-conducting wafer in which a spatially varying plasma density is photo-injected by a computer controlled light source. The varying plasma density alters the local dielectric constant of the wafer material and allows diffractive control over incident MMW radiation. Operation from 20 to 100 GHz is described, with beam scanning of 30 o in two-dimensions. Experimental results show that the beam can be scanned (hopped) in arbitrary directions at rates greater than 1000 hops per second with excellent control in software. Beam scanners based on this approach promise to be fast, inexpensive, and easily controlled.