ABSTRACT
This chapter presents a description of the physics of photoconductive switching at high powers and discusses the criteria used to design a photoconductive switch-based microwave source. It describes the types of ultra-wideband signals that may be generated using photoconductive devices and presents some experimental data that demonstrate the utility of the technique. The power density is a function of the electromagnetic field which, as will be shown later, is one of the fundamental limits on the system performance. The transverse electromagnetic parallel plate transmission line has the largest bandwidth and, when terminated by a matched impedance which is the shortest possible time for the energy to be completely transferred and therefore the output power is the highest. The center frequency of the microwave signal produced is dependent on the timing with which the switches are closed. Tunability and modulation of the signal are performed by delaying or advancing the time of arrival of the activating laser pulses.
