Development of radiated emi estimation algorithms for pcb emi expert system

The papers in this dissertation describe algorithms and techniques developed for the University of Missouri-Rolla PCB (Printed Circuit Board) EMI (ElectroMagnetic Interference) Expert system. The topics discussed in this dissertation are focused on the estimation of the radiated emissions from printed circuit boards and power bus noise. The first paper deals with radiated emissions due to voltage-driven sources. It is shown that the radiated fields due to a voltage-driven source may result in significant radiated EMI problems depending on the configuration of the board. A simple wire antenna model is proposed to estimate the radiation emissions. The parameters required for the model can be obtained either by simple closed-form expressions or using an electrostatic field solver, which usually requires less computational resources than a full-wave field solver. A closed-form expression for a parameter required by the simple antenna model is given in the second paper. The derived expression can be used when a microstrip line is the source of the radiation. The third and fourth papers discuss power bus noise issues related to rectangular power bus structures. The radiated emissions from power buses are discussed in the third paper. The effect of components on a printed circuit board is taken into account using a cavity model with a modified propagation constant. The last paper investigates the increase in the effective ESR (Equivalent Series Resistance) of a component with multiple power/ground pins. An equivalent circuit model was used to represent the multiple pins. The model shows that the effective ESR increases as the number of power/ground pins increases.