Design of a Low-Voltage Traveling-Wave Tube Based on Double-Corrugated Waveguide with Wide Grating Slow-Wave Structure

This paper proposes a double-corrugated waveguide with wide grating (DCWWG) slow-wave structure and applies it to the design of a low-voltage terahertz traveling-wave tube (TWT). To improve the TWT’s efficiency, a phase-tapered slow-wave structure is proposed. A response surface model is developed to identify the optimal tapering scheme, which is then further optimized using a genetic algorithm. Within the frequency range of 205–235 GHz, the phase-tapered DCWWG TWT exhibits significantly higher saturated output power and gain compared to the uniform DCWWG TWT. The maximum output power of the phase-tapered DCWWG TWT reaches approximately 26 W, representing an increase of about 47% over the 19 W maximum output power of the uniform DCWWG TWT. Overall, the phase taper technique substantially enhances the output performance of the DCWWG TWT.