SPURIOUS OSCILLATIONS IN INJECTED BEAM CROSSED FIELD AMPLIFIERS

摘要

A theoretical analysis of a certain group of nonlinear phenomena in octave IBCFA's is made. It specifically addresses the problem of frequency dependent gain enhancement and clustering of spurious oscillation in the passband at power levels far below saturation. The concept of passband gain modulation by Low Frequency instabilities and fluctuations is introduced. It is shown that in IBCFA devices with meanderline circuits, the actual operation inadvertently involves terminations for the RF interaction circuits which present fairly good matching conditions in the passband but results in a unity reflection coefficient at the output end for low frequencies (hundreds of MHz). Therefore LF oscillations or fluctuations are an insidious problem unless these tubes are equipped with sufficient additional RF circuit attenuation.