Active quasioptical Ka-band rf pulse compressor switched by a diffraction grating

Results of numerical calculations and experimental investigations of an active Ka-band microwave pulse compressor are presented. The compressor is based on a running-wave, three-mirror, quasioptical resonator utilizing a diffraction grating whose channels embody plasma discharge tubes that constitute the active switch. The principle of compression is based on rapidly changing the resonator’s output coupling coefficient (Q switching) by initiating plasma discharges in the grating channels. Excitation of the resonator was achieved with up to 250 kW of 34.29 GHz microwaves in 700 nS pulses from the magnicon at the Yale Ka-band Test Facility. A power gain of at least 7∶1 in the compressed pulse with a pulse duration of 10–15 ns was achieved.