Inductance and Capacitance Modeling of RF Board and High Speed Package Interconnects based on Planar EM Simulation

This paper describes a methodology to simulate the distributed inductive and capacitive effects introduced by the interconnects on RF board circuits and High Speed packages. This methodology is based on an equivalent RLC model, derived directly from the discretization of the planar electromagnetic field equations. We discuss the relation of the voltage and the current in the equivalent network with the electric and magnetic fields in the physical circuit. We also present a new technology based on mesh reduction to eliminate redundancy and hence reduce the order of the equivalent RLC network. This new technology comprises a generalization of the basis functions used in the disretization of the surface currents. The generalized basis functions allow for a more efficient meshing of complex geometrical structures in terms of polygonal shaped cells. The increased simulation performance is demonstrated in the examples. We present numerical simulation results for two real-life examples: an RF board interconnect layout and a high-density ball-grid array package.