Return path analysis is very useful in predicting radiation and current distribution from planar structures such as PCBs, MCMs and packages. However, it is very computation intensive and requires millions of meshes in reference planes. Special PEEC based techniques [1] have been used to calculate frequency dependent current distributions in these planes, which may have arbitrary shape. However, this required uniform meshing. A more general method based on Fast Multipole and variable mesh sizes

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... s used here to considerably speed up the process. In special cases, portions of the structure can be analyzed independently making parallel processing a practical solution to enhance speed. With all these enhancements, it is possible to analyze a complex whole board.