Analytical evaluation of the asymptotic impedance matrix of a uniaxial substrate with roof-top functions

An asymptotic technique is presented to solve the asymptotic part of the impedance matrix in the spectral domain for printed circuit structures on a uniaxial substrate by using roof-top subdomain expansions. The infinite double integral of the asymptotic part of the impedance matrix is reduced to a finite one-dimensional integral by performing the integral transform technique. The efficiency and accuracy of the proposed method are compared with those of the conventional method, and it is demonstrated that the proposed method reduce the computation and improve the accuracy for the anisotropic uniaxial case.