The propagation characteristics of signal lines embedded in a multilayered structure in the presence of a periodically perforated ground plane

The propagation characteristics of waves along a periodic array of parallel signal lines in a multilayered structure in the presence of a periodically perforated ground plane are studied. To analyze this structure, the spectral-domain immittance approach is used to derive the Green´s function. The surface current density on the conductors is expressed in terms of a set of rooftop subdomain basis functions. The boundary condition is then enforced in conjunction with the Galerkin procedure, leading to an eigenvalue problem for the propagation constant which is solved by the Newton-Raphson algorithm. The dispersion characteristics of these signal lines are studied for both balanced and unbalanced excitations with the relative permittivities of the various layers as parameters. Numerical results are presented and compared with available data. Extension of the present method to treat conductors with finite sheet resistances is also discussed