Visualization of Circuit Card EM Fields

摘要

This is the final report for Air Force contract F(41608-96-CA)116: Visualizationof Circuit Card EM Fields. Circuit cards (or circuit boards) of one type or another are used in nearly every electrical appliance used by the military or by commerce. This naturally includes computers, which are themselves used in many electrical appliances. To assure quality, all circuit board manufacturers use quality control testing to verify that the circuit board perform appropriately. There exist automated, readily available, and inexpensive testing mechanisms for unpopulated boards. However, for the testing of populated boards, the usual testing techniques are expensive due to the cost of construction of specialized test fixtures. Most board failures are due to either bad solder joints or faulty components. Either of these errors results in differing currents in the circuit board traces and in the components on the board. These differing currents result in a differing electromagnetic field radiated by the circuit board. This differing electromagnetic field can be used as the basis for a detection mechanism of errors.