Design and PIC Simulation of Ka-Band Periodically Loaded High Gain Gyro-Twystron

Abstract

In this article, the design and multimode analysis of a Ka-band, single cavity followed by a periodically dielectric-loaded (PDL) waveguide-based gyrotwystron operating in the fundamental TE01 mode have been presented. The present amplifier has been studied for its stability against the backward wave oscillations (BWOs) and the beam–wave interaction by using the linear and nonlinear multimode theory, respectively. Furthermore, the design of the present gyro-twystron has been validated by using a commercially available 3-D particle-in-cell (PIC) code. Moreover, a few key subassemblies, including a Y-shaped input coupler, triode-type magnetron injection gun (MIG) with ∼4% velocity spread, a curved collector, and a double-disk RF window, have been designed and studied for their performance behavior. The 3-D PIC simulation of the present gyro-twystron predicted ∼260-kW RF output power in the TE01 mode at ∼35 GHz. The gain, efficiency, and bandwidth are calculated as ∼54 dB, 40%, and 1.3 GHz, respectively. © 2022 IEEE.