Analysis of a microstrip line over a periodically perforated ground plane using the spectral domain method

Electromagnetic characterization of microstrip interconnects over a periodically perforated ground is important in electronic packaging. To reduce the complexity of the problem, microstrip lines are also assumed to be periodic so that only the solution to an unit cell is required. However, under this assumption, many practical interconnection configurations such as discontinuities cannot be analyzed. To circumvent this difficulty, a rigorous space-domain analysis has been presented in which equivalent magnetic surface currents on the perforations are also included in the analysis. However, the CPU is drastically increased. We present a spectral domain method in which the perforation on the ground plane is assumed periodic while the microstrip interconnects are not. The approach is similar to the antenna-radome interaction analysis presented by Chan and Mittra (1989).