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Characteristics of transverse electric and magnetic field transmission cells at extremely low frequencies
Author(s) -
Wood A. W.,
Joines W. T.,
Blackman C. F.
Publication year - 1987
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250080409
Subject(s) - magnetic field , electric field , transverse plane , physics , transverse magnetic , electrical impedance , electromagnetic radiation , electromagnetic field , nuclear magnetic resonance , optics , acoustics , engineering , structural engineering , quantum mechanics
Transverse electric and magnetic field (TEM) cells are often designed to subject samples to electromagnetic radiation of intrinsic impedance (E/H) that is the same as in free space, 377 ω. Earlier work has shown this value to be correct for the RF region above about 2 kHz. In this study, measurements of magnetic fields in the extremely low frequency regions and at DC indicate the E/H ratio to be around 300 ω for frequencies less than 2 kHz in cells of a particular design. This lower value indicates that care should be taken in estimating AC magnetic field intensities from electric field measurements in TEM cells at frequencies below 2 kHz.