LAUSR

This article presents the effect of choosing a different operating region on the output performance of a spatial harmonic magnetron (SHM). A 28-vane SHM with a backward spatial harmonic of ( $\pi $ /2)−1 operating mode at 136 GHz has been modeled and analyzed for performance study using CST-particle studio. The steady-state output power of 4.83 kW at 11.10 kV applied voltage with an efficiency of 5.61% has been obtained. An increment in the output power is observed on the application of higher anode voltage, but the efficiency saturates as the applied voltage reaches 0.4 times the threshold voltage. A close observation of the electron cloud or spokes reveals a greater expansion of the electron cloud toward anode as compared to the conventional magnetron. This expansion of the space charge cloud closer to the anode surface results in better beam wave interaction. It is this expansion factor, which is the part of the threshold voltage that perturbs the electron spokes of the fundamental mode but has little effect on the overall steady-state electron cloud.