Electrostatic simulation of a contactless test system for printed circuit boards

Abstract

The printed circuit board test industry continually requires faster, more accurate and more economical techniques to find manufacturing defects such as open and short circuits. Cirlog Corporation developed a prototype test system, capable of detecting manufacturing defects without contacting the board under test, based on electric field principles called the Contactless Test System (CTS) (U.S. Patent 5517110). This thesis gives an overview of PCB test equipment, the CTS technology and describes the utilization of electrostatic field simulations and experimental measurements in the continued research and development of the CTS technology. An equivalent circuit model is developed for the CTS and various simulations are conducted to determine and demonstrate the characteristics and capabilities of the technology. Simulation techniques utilized include a parallel plate model, empirical formulas and solving the CTS geometry as an electrostatic problem. The electrostatic solution utilizes the Method of Moments (MoM), to solve the integral equation that arises from Poisson's equation subject to boundary conditions. Dielectric regions are incorporated into the simulation models and their influence on the CTS technology characteristics are described. A Complex Images technique is described for multiple layer dielectric geometries. (Abstract shortened by UMI.)