Finite integration technique numerical modeling for EMC and signal integrity problems

Because it costs to solve electromagnetic compatibility (EMC) problems late in the development process, new methods have to predict the electromagnetic (EM) behavior of an equipment at the design stage. This proposal seems to be quite hard to solve because of the number of factors that influence the EM field. In this paper a software code based on the finite integration technique in time domain (FIT-TD) has been used and is presented. It is, associated to the perfect boundary approximation (PBA) technique, as efficient as the FD-TD method in terms of speed and storage requirements versus the number of mesh cells because the problem it solves is also explicit and it approximates curved objects without using too many mesh cells. As a validation a comparison between FIT-TD and PBA modeling and measurement of the shielding effectiveness (SE) of an enclosure is presented. Then three planar structures are investigated for signal integrity and EMC issues: an annular microstrip resonator which presents a high resonant effect, a lossy stripline which presents a dispersion phenomena, and EM radiation due to coupling from PCB traces to a heatspreader/heatpipe structure. For these three other case studies, results obtained with the FIT-TD and PBA modeling are compared to measurement and another numerical simulation.