Reflection dependence on frequency of overmoded slow wave structure and the influence of resonant cavity

The reflection properties of the TM01，TM02 modes of the circular waveguide by overmoded SWS are investigated by solving the Sparameters matrix with the method of the finite element method, and the difference between the reflection characteristics of two ports due to the asymmetry because of the introduction of the resonant cavity into one end of the SWS are analyzed. The numerical calculation results show that the reflection to the TM01 mode inputted into the port without resonant cavity increases while the reflection to the TM01 mode inputted into the port with resonant cavity decreases. The reasons that the introduction of the resonant cavity can reduce the needed period number of the SWSs and enhance the output microwave power efficiency are also demonstrated.