Optically-Activated GaAs Switches for Ground Penetrating Radar and Firing Set211 Applications

摘要

Optically activated, high gain GaAs switches are being tested for many different211u001eapplications. TWO such applications are ground penetrating radar (GPR) and firing 211u001eset switches. The ability of high gain GaAs Photoconductive Semiconductor 211u001eSwitches (PCSs) to deliver fast risetime pulses makes them suitable for their use 211u001ein radars that rely on fast impulses. This type of direct time domain radar is 211u001euniquely suited for the detection of buried items because it can operate at low 211u001efrequency, high average power, and close to the ground, greatly increasing power 211u001eon target. We have demonstrated that a PCSs based system can be used to produce a 211u001ebipolar waveform with a total duration of about 6 ns and with minimal ringing. 211u001eSuch a pulse is radiated and returns from a 55 gallon drum will be presented. For 211u001efiring sets, the switch requirements include small size, high current, dc 211u001echarging, radiation hardness and modest longevity. We have switched 1 kA at 1 kV 211u001eand 2.8 kA at 3 kV dc charge.