Detection and identification of electronic circuits based on their unintentional radiated emissions and an investigation of the effect of chassis connections on radiated EMI from PCBs

The thesis consists of two sections. Section 1 of the thesis describes a method for detecting and identifying electronic circuits based on their unintentional electromagnetic emissions. This concept can be applied to help find hidden electronic devices such as video cameras, active microphones, timers and computers. Section 2 of the thesis describes an investigation on the effect of grounding or floating printed circuit boards at chassis connections. Printed circuit boards are often mounted to a metal plate or chassis. Sometimes an electrical connection between the board and the chassis is made at the mounting points and other times no electrical connection is made. The results show that boards properly grounded to a chassis plate exhibit significantly lower radiated emissions. However improper grounding can significantly increase radiated emissions at some frequencies. This section of the thesis will be published in the proceedings of IEEE-EMC-2006 conference --Abstract, page iii