Numerical Studies of a New-Type Vircator With a Resonant Cavity

In order to improve the efficiency and obtain the output with pure fundamental mode ( TE
₁₁
mode), improvements are made on a vircator with a resonant cavity. The structure of the cathode is modified, and the radius of the output waveguide is decreased. By careful optimizations, microwaves at 2.26 GHz are obtained by simulation with an efficiency of 10%, and the output mode is TE
₁₁
. Cold-cavity simulations show that more than one resonant frequency exists in the TM
₀₁
band of the resonant cavity due to the existence of the coupling window. Though 2.26 GHz is not the strongest resonant frequency, microwaves at 2.26 GHz can be excited more easily. Therefore, the operating frequency is 2.26 GHz, and the operating mode in the resonant cavity is TM
₀₁
.