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Affiliation of Author(s):[1]Univ Elect Sci & Technol China, Sch Elect Sci & Engn, Chengdu 610054, Sichuan, Peoples R China;[2]South China Univ Technol, Sch Elect & Informat Engn, Guangzhou 510641, Guangdong, Peoples R China

Journal:IEEE TRANSACTIONS ON ELECTRON DEVICES

Key Words:Oscillators; Mirrors; Manganese; Couplings; Kinetic theory; Dispersion; Cyclotrons; Backward-wave oscillation (BWO); confocal circuits; gyrotron travelling wave amplifier (gyro-TWA); kinetic theory; near-cutoff oscillation

Abstract:In this article, key parameters that characterize field distribution and beam-wave coupling in confocal circuits are studied. The kinetic theory of confocal gyro-TWT considering launching loss is deduced based on it, which is capable of predicting the linear gain rate of confocal circuits with arbitrary mirror widths. Numerical results manifest that the output power/gain versus interaction position agrees well with the nonlinear results in the small-signal regime. In addition, main oscillations in confocal circuits including the near-cutoff oscillation and backward-wave oscillation (BWO) have been examined. Analytical expressions that can predict the near-cutoff oscillation threshold of uniform circuits without considering loss are derived and kz-f plots are introduced for lossy circuits. Furthermore, an algorithm that can automatically search the BWO start-oscillation thresholds of confocal circuits with arbitrary mirror widths has been developed.

First Author:Yelei Yao

Document Type:Article

Volume:66

Issue:11

Page Number:4957-4963

ISSN No.:0018-9383

Translation or Not:no

Release time:2025-05-23