Study of a 500-GHz Medium-Power Second-Harmonic Multiplying Gyrotron Traveling-Wave Amplifier With a Broad Frequency Range

• Published in: IEEE transactions on plasma science Vol. 52; no. 1; pp. 46 - 53
• Main Authors: Yeh, Yi Sheng, Li, Zong Ru, Pan, Yan Ru
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Broadband; Codes; Copper; Cyclotron resonance devices; Cyclotrons; Electron beams; Frequency conversion; Frequency ranges; Gyrotron traveling-wave amplifier (gyro-TWA); Gyrotrons; Harmonic analysis; harmonic multiplying gyro-TWA; low current; low voltage; Magnetic fields; Multiplication; Oscillators; Quadratic equations; subterahertz; Traveling wave amplifiers; Traveling waves
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2023.3345305

A harmonic multiplying gyrotron traveling-wave amplifier (gyro-TWA) allows magnetic field reduction and frequency multiplication. This study presents a low-voltage, low-current, 500-GHz second-harmonic multiplying gyro-TWA that produces a medium power of ~10 W over a broad frequency range (~5 GHz). An improved harmonic multiplying gyro-TWA featuring a distributed-loss structure achieves improved amplification performance and stability. Simulation results show that the involved spurious oscillations can be suppressed by high lossy-section resistivity, long lossy section, and short copper section. A tuned magnetic field is employed to achieve broadband frequency characteristics. The output power of the amplifier is a quadratic function of the input power. With a 12-kV, 0.3-A electron beam, the frequency range of the proposed amplifier is approximately 5 GHz for a 1-50-mW input power that can be provided by a 250-GHz commercial solid-state source.