Stability and Multimode Simulation Studies of ${W}$ -Band Uniformly Dielectric-Loaded Gyrotron Traveling-Wave Tube Amplifier

In this article, a nonlinear self-consistent, multimode analysis, and particle-in-cell (PIC) simulation of a uniformly dielectric-loaded (UDL) millimeter-wave gyrotron traveling-wave tube (gyro-TWT) amplifier has been discussed. A single-anode magnetron injection electron gun is designed to produce a relativistic electron beam of 100 kV and 5 A with a unity velocity ratio and 5% of axial velocity spread. The desired operating mode TE01 is fed by converting the TE10 rectangular waveguide mode through the Y-shaped power transducer. Both the multimode theory and PIC simulation results are agreed and predicted the saturated RF power of ~140 and ~145 kW at 92 GHz, respectively. A saturated gain of ~51 dB, a 3-dB bandwidth of ~5%, and a power conversion efficiency of ~28% are obtained. To collect the spent electrons, a collector is designed by using electron optics, E-GUN. The maximum heat wall loading at the collector surface due to a spent beam is calculated as 0.255 kW/cm
²
.