Fullwave analysis of multilayer microstrip lines

A new fullwave analysis of microstrip line structures with multidielectric layers is presented, using a hybrid approach that combines the finite-element method and the conformal-mapping technique. Wheeler´s mapping function is adopted to transform the half-infinite original domain into a finite image domain and to overcome the field singularity difficulty around the conductor edges in the original domain. Unlike the spectral-domain method, the present method needs no assumption of the singular current distribution on signal strip. Numerical results for effective dielectric constants, and characteristic impedances for various multilayer microstrip line structures are presented and discussed. Comparisons are also made of the computed results with the available ones, and good agreements are obtained