Cavity testing for W-band gyroklystron amplifiers

Summary form only given. The Naval Research Laboratory has undertaken a 94 GHz gyroklystron amplifier development program for radar applications. This program comprises both in-house development as well as cooperative development between NRL, Communication and Power Industries, Litton Electron Devices, and the University of Maryland. These devices utilize multiple cavities tuned to different frequencies, typically in the range of 93 to 95 GHz to achieve the desired gain, power, and bandwidth requirements. The cavities operate in the TE/sub 01/ mode with Q´s in the range of 100-200. Due to the sensitivity of cavity performance characteristics to manufacturing tolerances, it is essential that the cavity characteristics be measured after assembly. For the NRL/industrial amplifier, space considerations preclude usage of apertures in cavities for diagnostics, so we rely on TE/sub 01/ axial transmission evanescently coupled through cavity irises to determine the resonant frequency and Q. Specifics of the measurement depend on the cavity type to be measured; input, intermediate, or output.