Multiphysics Characteristics of a 600 W Broadband Ka-Band Pseudo-Periodic Helix Traveling Wave Tube

• Published in: IEEE transactions on electron devices Vol. 71; no. 3; pp. 2105 - 2110
• Main Authors: Ma, Mingjing, Xie, Yang, Shen, Changsheng, Chen, Zhaofu, Cheng, Hongxia, Bai, Ningfeng, Sun, Xiaohan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Back-wave oscillation; Broadband; Electron beams; Electrons; Extremely high frequencies; Frequency ranges; Harmonic analysis; helix traveling wave tube (TWT); Impedance; Metals; multiphysics characteristics; Power amplifiers; Power generation; pseudo-periodic slow wave structure (SWS); Temperature distribution; Thermal stability; Traveling wave tubes; Traveling waves
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2024.3350558

A pseudo-periodic helix slow wave structure (SWS) is proposed to provide high output power with wide bandwidth in Ka-band. The support rods with curved metal provide flat dispersion and high interaction impedance, while a pseudo-periodic SWS suppresses backward oscillation and improves output power. The simulation results show that the traveling wave tube (TWT) with this pseudo-periodic helix SWS produces an average output power of more than 600 W in the frequency range from 26 to 36 GHz with beam voltage and beam current of 11.287 kV and 0.3 A, respectively, with a maximum output power of 700 W at 31 GHz, corresponding to a maximum gain of 42.8 dB and an electronic efficiency of 20.5%. The multiphysics analysis reveals the influence of the high-frequency losses on the temperature distribution in the operating condition. The results indicate that the maximum temperature in the last 15 circles is concentrated at the end of the pseudo-period helix SWS with a peak temperature of 304 °C, resulting in better heat dissipation performance, easier structural fabrication, and less deformation.