Research of G-band extended interaction klystron broadband beam-wave interaction system

Extended interaction klystron adopts multi-gap distributed interaction resonantor and all metal planar structure, which makes the interaction circuit short and the gain per length high. Its planarization structure is compatible with modern micromachining technology, which has made it a research hotspot to develop terahertz high-power source. Further extending the bandwidth of the extended interaction amplifier becomes the key technology to expand its application. A G-band 5-cavity multi-gap beam-wave interaction circuit is designed in this paper. Stagger tuning technology is used to expand the cluster bandwidth and filter loading technology is used to expand the output circuit bandwidth. Structural parameter optimization and output characteristic simulation by CST show that when the electron beam voltage is 19 kV, the current is 300 mA and the input power is 120 mW, the output power is 222 W, the electron efficiency is 3.89%, the gain is 32.67 dB, and the 3 dB instantaneous bandwidth reaches 1.5 GHz.