Design of Optically Controlled Microwave Switch for Reconfigurable Antenna Systems

A novel optically controlled microwave switch has been designed for applications in reconfigurable antenna systems. This new configuration consists of a microstrip transmission line with a gap etched in the metal strip and two identical microstrip square open-loop resonators. A piece of silicon photoconductive dice is placed on the etched gap. With no optical illumination the switch exhibits a well-defined stopband. The isolation is about 53 dB at the resonant frequency of 11.65 GHz. When light is focused onto the silicon dice, the photoconductivity effect suppresses the bandstop characteristic and induces the switch at "ON" state. The simulation result shows that there is a distinct improvement of the isolation by 20 dB than the optically controlled switches previously reported.