Analysis of electromagnetic wave transmission through a choke usingFE-BIM with arbitrary incident angle/polarization

The performance of a microwave choke is analyzed by the finite element-boundary integral method (FE-BIM) for an incident wave with arbitrary angle/polarization. The equivalence principle is used to divide the whole region into three subregions: incident region, choke region, and transmitted region. The functional in the choke region is derived with an appropriate boundary condition between subregions. The choke region is discretized by rectangular meshes. Vector edge elements are used for the representation of the cross-sectional electric field, while node elements are used for the axial-directional electric field. The electric fields in the cross section of the choke are determined by the Rayleigh-Ritz procedure. The performance of a microwave choke is analyzed by investigating the transmission characteristics of the choke for a plane wave with varying incident angle and polarization. Experiments have been done using a rectangular waveguide with the choke structure inside. The results agree very well with the theoretical prediction