Simplified modeling of parallel plate resonances on multilayer printed circuit boards

Multilayer printed circuit boards (PCBs) are currently used in various areas of electronics such as telecommunications. However, high crosstalk between signal vias can cause degradation of performance for these kinds of structures. Resonances of parallel ground or power planes can increase this crosstalk. In this study, a simplified approach to the modeling of these resonances is described. It is assumed that the fields inside the board have characteristically only two-dimensional (2-D) variation. When this hypothesis is valid, it is shown that resonances can be measured on two-layer prototyping boards and simulated using a 2-D finite-difference model. It is additionally noted that a previously suggested method of using coaxial ground vias to suppress coupling between vias is not necessarily effective if there are resonant parallel plates on the board. Agreement between measured and modeled results is good enough for practical design purposes. The main advantages of the method used in this study compared to the more robust three-dimensional (3-D) simulation models are savings in time and costs. Additionally, prototyping is much easier on two than multilayer boards.