A technique of electromagnetic interference measurements with high-impedance electric and low-impedance magnetic fields inside a TEM cell

Transverse electromagnetic (TEM) cells are usually used to perform electromagnetic interference (EMI) measurements of equipment inside the cell in a plane wave-field environment. A newly developed technique of generating predominantly high-impedance electric or low-impedance magnetic fields inside a TEM cell for EMI measurements of relatively small printed circuit boards (PCBs), electronic devices, etc., is described. The technique simulates environments similar to the near-field EMI environment for intrasystem EMI/EMC (electromagnetic compatibility) studies. Variations of electric and magnetic fields, as well as impedances along the length of the cell, are given. The results indicate that a test region of reasonable size exists in the cell over which the field amplitudes are uniform within ±1 dB