An efficient grid placing technique for 2-D method of moments analysis of coupled line structures

In this paper an analysis routine is presented for a two dimensional method of moments analysis of coupled line structures to find the capacitance matrix. A method is proposed to significantly reduce the number of unknowns. The method borrows from physical optics to predict electrical 'shadows' where the charge density is negligible and can be ignored. This new method is implemented, and a significant improvement in analysis time is achieved with very little loss of accuracy. The analysis routine is used in an optimization loop to synthesize an interdigital filter which displays excellent performance.