Prepulse suppression in microwave pulse-compression cavities

Abstract

It is possible to generate high-power microwave pulses with fast rise time by using resonant cavities to obtain power gain from pulse compression. In the usual case, especially when normal-conducting cavities are used, the principal output pulse from a pulse-compression device is preceded by a precursor signal that may be only 40 dB below the main pulse. For some applications this large a prepulse is unacceptable. We have developed a prototype normal-conducting, x-band, pulse-compression cavity in which the prepulse is suppressed by more than 70 dB. When this cavity is driven by a 20-kW source, output pulses with 200-kW peak power, 5-ns pulse width, and sub-nanosecond rise time can be obtained. We have also built an s-band cavity that has produced pulses of 5-ns width, 200-MW peak power, and under 3-ns rise time. The s-band cavity is typically driven at 5–10 MW and has a prepulse that can be more than 80 dB below the peak of the main pulse.