High-power waveform generation using photoconductive switches

In the nanosecond time regime gallium arsenide photoconductive devices are nearly ideal circuit elements for the generation of wideband high-power waveforms. The ability to activate these devices in an avalanche mode further enhances their utility since semiconductor lasers with nanojoule-range pulsed output can enable turn-on. Furthermore characteristics of gaffium arsenide provide the ability to fabricate switches with significant DC hold off capability. In general microwave matching requirements tend to be in opposition to high-voltage integrity constraints. This creates formidable design challenges. Careful compromises in the packaging design have led to megawatt-level peak power outputs at multi-gigahertz frequencies from surprisingly small devices. Work to date has concentrated on monocycle generation for use with a wideband antenna structure. Resultant radiated outputs have applications in ultrawideband radar electronic warfare and communications.