A technique of electromagnetic interference measurements withhigh-impedance electric and low-impedance magnetic fields inside a TEMcell

摘要

Transverse electromagnetic (TEM) cells are usually used to performelectromagnetic interference (EMI) measurements of equipment inside thecell in a plane wave-field environment. A newly developed technique ofgenerating predominantly high-impedance electric or low-impedancemagnetic fields inside a TEM cell for EMI measurements of relativelysmall printed circuit boards (PCBs), electronic devices, etc., isdescribed. The technique simulates environments similar to thenear-field EMI environment for intrasystem EMI/EMC (electromagneticcompatibility) studies. Variations of electric and magnetic fields, aswell as impedances along the length of the cell, are given. The resultsindicate that a test region of reasonable size exists in the cell overwhich the field amplitudes are uniform within ±1 dB