Modeling and measuring the reflection and transmission of a silicon wafer in the X- and Ka-bands under illumination of light in a closed waveguide structure

In the past two years, extensive research has been carried out at IRCTR (In ternational Research Centre for Telecommunication-Transmission and Radar) i n order to analyze and model the reflection and transmission coefficients o f a semiconductor, i.e., doped silicon, under illumination of light. It was found that the characteristics of the semiconductor material could substan tially be changed once it is illuminated with light. This property of the s emiconductor material can be used to realize a nonmechanical beam deflector that can form and scan a beam of millimeter-wave (MAW radiation at a rapid rate. The preliminary measurements in a closed waveguide structure show th at there is a total reflection of MMW and microwave (AW) power after the la ser is turned on. The laser light causes a considerable change in the equiv alent conductivity of the silicon wafer, changing it from an insulator to a good conductor. The reflection and transmission are modeled using the S-T matrix of the total microwave network. There is a good similarity, in the b ehavior of the theoretical and measurement results. (C) 2001 John Wiley & S ons, Inc.