Prediction of voltage induced between wirings on printed wiring board by external fields

Predicting the voltage induced by external fields in the wiring on a printed wiring board (PWB) is an effective way to prevent malfunctions of electronic apparatus caused by electromagnetic fields. This paper examines factors contributing to the voltage induced between wirings and a method for predicting voltage according to the incident angle of external fields. Experiments showed that the voltage between wirings changes at a constant rate according to the incident angle of external fields for a given frequency and distance between wirings. Evaluation using this rate of change is effective in analyzing factors affecting voltage between wirings. It was clarified that the main factors are phase difference caused by the difference in distance between the disturbance source and each wiring and the effect of a finite ground. As a result of the finite ground effect, only the diffracted waves at the ground edges were assumed and analyzed, and the results of the analysis of voltage between wirings were shown to agree closely with the experiment results.