Efficient spectral domain analysis of multilayered shielded microstrip using two super convergent series

An efficient approach to speed up the spectral domain analysis for the general case of shielded microstrip has been presented. It uses asymptotic expansion for the Bessel´s function and the Green´s function which are involved in the computation of the elements of the Galerkin matrix. The coefficients in the asymptotic expansion of the Green´s functions are obtained by a combination of analytical and numerical approaches. Efficient computation of the infinite summation obtained after leading term extraction is done using two different super convergent sine cosine series. Very accurate results for the propagation constants in the general case of a multilayered shielded microstrip line can be obtained using a few basis functions.