High-order mode interaction structure for a W-band CW sheet beam extended interaction klystron

To solve the problem of mode competition in high-order working modes, this paper presents a fast design method based on TM31-2π for dumbbell shaped extended interaction cavity. Based equivalent circuit theory, high-frequency characteristics structure are studied. In addition, we propose W-band continuous wave sheet beam klystron circuit. The was driven by 20 kV and 0.85 A electron beam, with 3.2 × 0.3 mm2 section. focused 0.8 T permanent magnet system. system adopts five five-gap cavities, output symmetrical waveguide. 3D particle-in-cell simulation shows that more than 1.5 kW power can be obtained at an input 0.12 W, efficiency gain 9.2% 41.2 dB, respectively.