On the Improvement of Volume-Surface Integral Equation Using the Combined Enforcement of Normal and Tangential Boundary Conditions

In the moment method solution of the volume-surface integral equation (VSIE), the normal and tangential boundary conditions are combined together and explicitly enforced on the perfect electric conductor (PEC)-dielectric interfaces. The number of volumetric unknowns is therefore reduced and the solution accuracy is improved. Based on the proposed scheme, when a dielectric tetrahedron is terminated by a PEC triangle, three expansion coefficients of the four SWG base defined on this tetrahedron are straightly determined.