Stepwise frequency tuning of a gyrotron backward-wave oscillator

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1827217· OSTI ID:20657988

Chang, T H; Chen, S H ^[1]

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1. Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China)

The gyrotron backward-wave oscillator (gyro-BWO) features broadband tunability, but ragged tuning curves are frequently observed experimentally. Accordingly, a Ka-band gyro-BWO experiment with external circuit mismatch was conducted to examine its tuning properties at two reflected strengths: one is slightly mismatched (15 dB reflection) and the other can be categorized as matched (30 dB reflection). Stepwise frequency tunings by varying the magnetic field, the beam voltage, and the beam current were observed under mismatched conditions. A self-locking model was introduced using the concept of injection-locking, where the output and reinjected signals tend to form a stable phase relation, favoring certain discrete oscillation frequencies. The observed frequencies agree closely with the calculated frequencies. Smooth tuning curves were also obtained, revealing a remedy for the stepwise tuning of a gyro-BWO.

• OSTI ID: 20657988
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM CURRENTS
MAGNETIC FIELDS
MICROWAVE AMPLIFIERS
OSCILLATORS
TUNING