Characteristics of transverse electric and magnetic field transmission cells at extremely low frequencies.
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 omega. 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 omega 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.
Wood
A W
AW
Department of Physics, Swinburne Institute of Technology, Hawthorn, Victoria, Australia.
Joines
W T
WT
Blackman
C F
CF
D004560:Electricity; D055590:Electromagnetic Phenomena; D008280:Magnetics; D008722:Methods