Electromagnetic Susceptibility Measurements Using a Mode-Stirred Chamber

Within the electromagnetic compatibility community it is recognized that there is a need for better methods to measure the radiat1 2 3 ed susceptibility of electronic systems. ' ' Free-space measurement facilities are economi­ cally unattractive, and the usual recourse is to conduct susceptibility tests within shielded rooms. Shielded room data are not, however, solely indicative of the test specimen characteristics; such data are influenced by room characteristics such as size, shape, and loss as well as location of the specimen and associated test equip­ ment within the room. It is easy, however, to convert any standard shielded room into a "mode-stirred" chamber wherein radiated susceptibility tests can be performed with results that are accurate, repeatable, and independent of test set-up. The problem of relating free-space and mode-stirred environ­ ments is approached in two ways, with the end result being a calibration graph that relates chamber input power to equivalent plane wave power density inside the chamber. The accuracy of mode-stirred chamber data is demonstrated by comparing susceptibility profiles from both free-space and modestirred test environments.