Design and Multipactor Analysis of a High Power RF Window

This paper presents the design of a high power RF window for X-band megawatt class pulsed coaxial magnetron. In this proposed design, overmoded cavity, with $\mathbf{TE}_{012}$ like mode (mixed with $\mathbf{TE}_{312})$ is considered instead of conventional pillbox cavity. Frequency domain simulation is carried out in CST and return loss, insertion loss, VSWR are obtained as 51.52 dB, 0.07 dB, and 1.005, respectively at 9.3 GHz. Mixed mode operation makes the bandwidth broad, and 40.8 MHz bandwidth is achieved for VSWR less than 1.05. The multipactor analysis is carried out in SPARK3D, and multipactor threshold is obtained as 16 MW. This makes the window suitable for the operation up to 16 MW peak power at 9.3 GHz.