Efficient simulation of Power/Ground planes for SiP applications

Packages for modem mixed signal systems in package (SiP) require split planes and power islands to isolate multiple power supplies. To reduce design iterations due to signal integrity issues, the frequency response of the package needs to be obtained accurately at an early stage of the design. Full-wave EM solvers are generally the most accurate tools available. However, the high time and memory required by such tools relegates their use to final verification, at which stage design iterations are expensive. The finite difference method has been shown to be efficient in simulating single plane-pair structures with slots as long as one plane is completely solid. Also, the multilayer finite difference method (M-FDM) can accurately model multilayer structures with apertures, so long as there are no power islands. In this paper, a formulation for efficient simulation of multilayer structures with split planes has been investigated. Further, a method by which transmission lines can be integrated with a power distribution network containing apertures and split planes has been discussed. The formulation has been validated by comparing results with full-wave EM simulations.