Design of high-power and wide-band G-band third harmonic amplifier

In order to meet the demand of high-power and wide-band signal sources for G-band vacuum electronic devices, the research on G-band third harmonic amplifier is carried out. The amplifier utilizes the third harmonic current in the nonlinear beam-wave interaction of E-band TWT, and realizes G-band electromagnetic wave amplification by cascading harmonic interaction section. The design scheme of high performance and practical G-band wide-band high-power source adopts folded waveguide slow wave structure with modified circular bends, and the G-band third harmonic amplifier is simulated and optimized by using the microwave tube simulator package (MTSS) software. The result shows that the device can obtain harmonic output power greater than 3.6 W in the range of 15 GHz, conversion gain＞33.3 dB, and electronic efficiency＞0.36%. Compared with other miniaturized Terahertz radiation sources in this band, it has superior performance in terms of output power and bandwidth, which provides a design basis for the subsequent research of G-band third harmonic amplifier.