High Power and Broadband W-Band Gyro-TWT in TE ₀₂ Mode With Zero-Drive Stability

This article presents the first successful development and experimental demonstration of a W-band gyrotron traveling-wave tube (gyro-TWT) operating in the high-order TE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>02</roman></sub> mode with zero-drive stability, high power, and broadband performance. Critical to this advancement lies in the detailed optimization of the axial magnetic field in the interaction region and the precise tailoring of lossy ceramic parameters. As a result, the oscillations of competing modes are effectively suppressed, and the associated excessive thermal load in the interaction region is significantly mitigated. The experimental measurement demonstrates sustained output power exceeding 125 kW across the 92–100 GHz with the pulsed operation of 10% duty cycle and 1-ms pulsewidth. Besides, the developed device achieves excellent amplitude and phase stability, with less than 0.33 dB amplitude variation and phase fluctuations within 8.67<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∘</sup> across the bandwidth. The implementation of high-order modes endows gyro-TWTs with the potential to generate hundreds of kilowatts of power in millimeter-wave and terahertz regimes, providing a promising foundation for future millimeter-wave and terahertz source applications.