Comparison of different implementations of VIE method

A volume integral equation (VIE) formulation was developed by Zhou and Shafai, which can be used for the analysis of scattering from general material bodies. Conductors are treated as a dielectric by letting the permittivity approach infinity. The formulation uses the dyadic Green´s function, which is singular when the source and field points coincide. Removing this singularity gives a source dyadic term that is geometry dependent (Yaghjian 1980). In application of the moment method to solve the volume integral equation, using pulse type basis functions, one must sub-divide the object into small cells. With different cell shapes one needs to use the corresponding source dyadic terms, that may influence the performance of the solution algorithm. In this paper, we present an analysis of the dependence of the solution on the cell shape and size. Applications to antenna radiation patterns of circular cylindrical dielectric resonator antennas in particular are discussed.