Comparison of BBSPICE to PEEC Equivalent Circuit Models for Simulation of Floating PCB Above Ground Plane

Floating, i.e. not locally grounded, printed circuit boards (PCBs) at the end of a long harness and above a large ground plane are common in automotive applications. A problem in modeling such setups is the missing ground reference at the PCB side. In this work, two equivalent circuit models are extracted from PCB design data, one based on a broadband SPICE (BBSPICE) netlist generated from S-parameter simulation and the other obtained by partial element equivalent circuit (PEEC) method. They are compared against measurements results of a demonstrator PCB in above described setup. Investigations include the verification of both modeling approaches with respect to low frequency behavior, broadbandness, sensitivity to PCB circuitry modifications and grounding scheme, as well as model generation effort and simulation times.