Improving the numerical efficiency of the method of moments for printed geometries

The rigorous and numerically efficient analysis of printed geometries in a multilayer medium has been a major research topic in computational electromagnetics because of the common use of these structures in monolithic microwave integrated circuits and in the design of printed antennas. It has been demonstrated that the use of the spatial domain method in conjunction with the closed-form Green's functions for the solution of the mixed-potential integral equation significantly improves the computational efficiency. This improvement is due to the elimination of the numerical evaluation of the slow-convergent and highly oscillatory Sommerfeld integral by approximating it with a finite series of complex functions. This approach results in two-dimensional integrals over finite domains with the smooth integrands as the method of moments (MoM) matrix elements. A technique of reducing the remaining double integrals to single integrals is presented and the improvement in the computational efficiency is demonstrated for a microstrip line.