SPECTRAL-DOMAIN FORM OF NEW VARIATIONAL EXPRESSION FOR VERY FAST CALCULATION OF MULTILAYERED LOSSY PLANAR LINE PARAMETERS

A new spectral domain formulation of the propagation characteristics f or planar and coplanar lines is presented. It is based on a newly esta blished variational principle, valid for a spatial as well as for a sp ectral formulation. In combination with conformal mapping, it drastica lly reduces the complexity of the numerical computation and leads to r apidly convergent results even when higher order modes are considered. Mathieu functions are shown to be very efficient expressions for tria l fields of the dominant and the higher order modes in slots. Calculat ion is fast: it is made on-line on a regular PC. Results obtained on o pen and shielded lines have been successfully checked with new experim ental data and with previously published data. The method is general e nough to accommodate gyrotropic substrates. The paper however is limit ed to isotropic media.