Analytical evaluation of the asymptotic impedance matrix of a grounded dielectric slab with roof-top functions

An analytical technique is derived to solve the asymptotic part of impedance matrix elements for printed circuit structures using roof-top subdomain expansions. The key to this problem is the analytical transformation from an infinite double integral to a suitable finite one-dimensional (1-D) integral. The newly developed formula is applied to the monostatic radar cross section (RCS) of a microstrip patch. Comparisons are made with measurements and conventional method of moments predictions.