ANALYSIS OF LOSSY PLANAR TRANSMISSION-LINES BY USING A VECTOR FINITE-ELEMENT METHOD

The vector finite element method with hybrid edge/nodal triangular ele ments is extended for the analysis of lossy planar transmission lines. In order to handle lossy conductor transmission lines, the present ap proach includes the effect of finite conductivity of a lossy area, and the dissipations in metallic conductors and dielectrics are calculate d directly by considering a complex permittivity for the lossy region of interest. Propagation constant formulation is used in the FEM, whic h avoids spurious solutions absolutely and can handle sharp metal edge s in inhomogeneous electromagnetic waveguides. Numerical examples are computed for microstrip lines, finlines, and triplate strip lines. The results obtained agree well with the earlier theoretical and experime ntal results, and thus show the validity of the method. Also, the curr ent distributions on the lossy microstrip lines with finite strip thic kness and isotropic substrates are presented.