High Efficiency Deflection Modulated Microwave Generator Study.

Abstract : This report describes a study of the deflection of the system in deflection modulated microwave generators (gyrocons). A general deflection theory was developed, based on a relativistic beam formulation and a first order expansion of Maxwell's field equations. It includes the effect of dc space charge forces on the beam size as well as a distortion of the beam cross section due to the RF interaction. The theory was applied to cavities with electric deflection fields. Such cavities were experimentally evaluated by cold tests and appear to be superior to the commonly used magnetic deflection cavities. A unique design approach makes it possible to achieve a circular beam deflection with a single RF signal. Multicavity deflection systems, in which the input cavity is followed by floating cavities that are excited by the deflection modulated beam, can provide high gain, typically 50-55 dB with three cavities. General design curves relating optimum beam perveance to other operating parameters and desired conditions at the output ring resonator were derived, but the output cavity itself was not part of the study. (Author)