Multipactor Effect Analysis and Design Rules for Wedge-Shaped Hollow Waveguides

A numerical model for predicting the multipactor breakdown effect in wedge-shaped hollow waveguides is presented in this paper. The computation of electromagnetic fields is based on the boundary integral-resonant mode expansion method, which provides the modal chart of hollow waveguides with any arbitrary cross section. The advantage of using wedge-shaped waveguides with respect to conventional rectangular ones is the deviation of the resonant paths of the electrons toward regions with lower voltages, thus reducing the probability of multipactor threshold for certain input power. To validate this method, our results have been compared with simulations from previous theoretical studies. Once the simulation tool is validated, it is used to predict the multipactor threshold of wedge-shaped waveguides with different symmetric inclination angles of their horizontal plates. Finally, susceptibility curves as the ones already available for rectangular waveguides are presented. These charts are useful for designing innovative waveguide geometries with improved multipactor-free working power ranges.