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

Abstract

Transverse electromagnetic (TEM) cells are usually used to perform electromagnetic interference (EMI) measurements of equipment inside the cell in a plane wave-field environment. This paper describes a new technique of generating predominantly highimpedance electric or low-impedance magnetic fields inside a TEM cell for EM1 measurements of relatively small size printed circuit boards (PCBs), electronic devices, etc. The technique simulates environments similar to the near-field EM1 environment for intrasystem EMI/EMC studies. Variations of electric and magnetic fields, and impedances along the length of the cell, are given. The results indicate that a reasonable size test region exists in the cell over which the field amplitudes are uniform within 2 1 dB.

A methodology to generate a time-varying adjustable wave impedance inside a TEM cell

“…The authors of [2] varied the load impedance of a TEM cell to obtain various known field strengths and wave impedances inside a TEM cell. The authors of [3] [4] excited the TEM cell at both ports using sinusoidal waveforms. This paper introduces a technique where arbitrary timedomain signals drive the TEM cell at both ends.…”

Near-Field Radiation From Commercial Cellular Phones Using a Tem Cell

“…Imaida et al and Wang et al, in order to study the effects of in vivo near-field exposure on rodent brain and liver carcinogenesis, have used especially designed 'exposure boxes' to reproduce the cellular telephones [10,11]. Another study to simulate a near-field EMI environment was reported by Das et al where they fed the in-phase and out-of-phase signals into both ports of the TEM cell [12]. None of these efforts, however, utilized commercially available cellular phones as the sources of EM exposure.…”

Straight coupled transmission-line cell for generating standard electromagnetic fields

“…The SPW has broadband characteristics compared with the DPW. However, the DPW can provide a dominant H-field (wave impedance 0 ) and a dominant E-field (wave impedance ) [9]- [11]. Recently, the authors proposed a bent coupled transmission-line (BCTL) cell whose inner conductors are bent in the tapered section [12].…”