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Detection of Quasi-Static Electric Fields Radiated by Electrically Small Emitters



David A. Hill, Kenneth H. Cavcey


This report presents the theory for near-field detection of quasi-static electric fields produced by electrically small emitters that radiate as small electric dipoles. The intended application is the detection of electronic timers of the type that could be used in bomb detonators. The search antenna could be either a linear dipole or a monopole antenna with a circular ground plane. Reciprocity is used to show that the induced open-circuit voltage is proportional to the electric field of the search antenna at the dipole source location when the search antenna is used in the transmitting mode. Comparison detection measurements have been made at a frequency of 200 kHz, and the measured open-circuit voltage falls below the theoretical prediction. Also, the background noise fields are higher than expected from published values. Consequently, the detection range is much shorter (10 to 20 cm) than expected, and the method does not look promising for timer search applications.
NIST Interagency/Internal Report (NISTIR) - 5096
Report Number


dipole moment, electrically small emitter, linear dipole antenna, monopole antenna, noise spectral density, quasi-static electric field, reciprocity


Hill, D. and Cavcey, K. (2000), Detection of Quasi-Static Electric Fields Radiated by Electrically Small Emitters, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD (Accessed June 23, 2024)


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Created June 1, 2000, Updated February 19, 2017