Operation of a double cavity, microwave pulse compression system with phase controlled output

Summary Form only given, as follows. Ultrashort microwave pulses of high peak power can be generated by switching the impedance of a high-Q S-band microwave cavity. For a given cavity, rapid closure of a gaseous plasma switch as a result of localized electron density growth enhances the coupling of the output port while greatly reducing that of the input port. A series of homodyne measurements using fast solid-state mixers has demonstrated the existence of a constant phase relationship between input pulses (typically 1 mu s FWHM) and output pulses (typically 4 ns FWHM). The authors have therefore constructed a double-cavity system designed for simultaneous parallel operation of both microwave cavities with input phase control on one. The combined short-pulse output of both cavities has been observed with different relative phasing between them. As a result of phase shifting over an interval exceeding pi radians, peak power output ranges from +67 dBm to +81 dBm for a fixed input level of +73 dBm (20 kW). These output levels correspond to the superposition of two short pulses summed out of phase (by pi radians) and in phase, respectively. The combined result for the out-of-phase case is not completely eliminated, since the output field amplitudes from each cavity are not identical.<>