Deembedding the effect of a local ground plane in electromagnetic analysis

In electromagnetic analysis of complex planar circuits, it may be necessary to use internal ports, e.g., in locations where surface mount devices might later be attached. These internal ports require a local ground plane for ground reference when access to the global ground reference is unavailable. Even if perfectly conducting, use of such a ground plane still introduces excess phase in the local ground currents. This paper describes how to remove the effect of a lossy or lossless local ground, even including multiple closely spaced ports