Methods for measuring parameters of ultra-wideband microwave radiation

Abstract

The plasma source of ultra-wideband (UWB) microwave radiation was developed. Operation of this source is based on amplification of the relativistic electron beam (REB) noise. The middle frequency of UWB amplifiers of this type is determined only by the plasma density and does not depend on duration of the high-voltage pulse at the cathode. This allows obtaining rather long signals with durations of about 200–300 ns and tuning the signal middle frequency from 2.2 to 3.8 GHz by means of varying the plasma density. A number of problems were solved, which occur in the course of measuring the UWB microwave signal parameters. In particular, a new method for measuring signal energy was developed, the optimal length of the receiving antenna used for recording the UWB radiation spectra was chosen, and the effective potential of the plasma UWB source was estimated. It was demonstrated that the energy of microwave signal is more than 10 J. The effective potential of the plasma UWB source was found to be approximately 400 kV for the signal with a middle frequency of 3 GHz that is comparable to that of other UWB microwave sources. It was also shown that the spectrum of the plasma UWB source is determined by its amplification band and by the oscillation spectrum of the current generated by the explosive emission cathode.