A Comparison of Finite vs. Infinite Plane Models of Reference Conductors in Electronic Packages

The accuracy of two layered-medium integral-equation approaches are evaluated using a benchmark package-scale microstrip line: (i) In the typical approach, where dielectric layers are extended to infinity using Green's functions, the currents in/on all conductors (here, a signal line and ground plane) are discretized. (ii) In the reduced-domain approach, where large reference conductors are also extended to infinity using Green's functions, the currents in/on a reduced set of conductors (here, only the signal line) are discretized. The approaches are contrasted by computing network parameters of the microstrip line using lumped-port models and diminishing port-truncation effects using a de-embedding technique. It is shown that the S11 parameter found by the typical approach is highly sensitive to the ground-plane mesh density under the signal line and requires finer meshes to reach to the accuracy of the reduced-domain approach.