Investigation of a microwave pulse compressor with a Magic-tee-based plasma interference switch

A microwave pulse compressor with a Magic-tee as an interference switch was investigated in numerical simulations and experimentally. If the compressor cavity is connected to the H- or E-arm of the Magic-tee with shorted side arms, the necessary condition for the microwave energy storage is the identicalness of the shorted arms regardless of the frequency. It means that the compressor operation in different cavity eigenfrequencies is possible without mechanical tuning. We have studied the two-frequency S-band compressor. Two characteristic geometries corresponding to different regimes of the microwave energy accumulation and release were tested using input pulses of 200-400 kW power, 2.4 μs duration, and variable frequency, 2.8 to 2.9 GHz. The geometries are characterized by an RF electric field in the interference switch that is higher or lower than the field in the cavity. For both geometries, the nanosecond output pulses in two resonant frequencies were obtained; the maximal peak output power measured was ~1.8 MW. The efficiency of the microwave extraction was limited by either an insufficient coupling to the tee output arm (in the case of a high field in the tee) or non-uniformity of the plasma discharge (in the case of low field in the tee).