Study of a rectangular beam extended interaction klystron in G-band

A multi-gap ladder-type resonant cavity with rectangular beam is designed for G-band extended interaction klystron (EIK). The periodic long-gap and short-gap alternated is applied in this structure. By theoretical analysis and optimal design, the structure parameters of cavity working at π mode are finally obtained. Through PIC simulation of six-cavity model, the results show a good output stability and mode competition suppression. With the operating voltage 16.5 kV, operating current 0.30 A and driving power 50 mW, the output power 271 W, efficiency 5.5% and 3dB bandwidth 670 MHz is achieved.