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Proceedings Paper

Resonance of input impedance of bow-tie antenna placed on ground surface
Author(s): Fan-nian Kong
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Paper Abstract

In the paper we have derived the following equation 4 f0 Lequi = c/sqrt(?equi ) where f0 is the resonant frequency of the antenna input impedance, c is the speed of light, Lequi and equi are respectively the equivalent length of antenna and the equivalent dielectric constant of the medium formed by halfspace ground and half-space air. When measuring in air, the dielectric constant is known. One can obtain the antenna equivalent length from the measured fo, by using the above equation. When Lequi is obtained, one then can calculate ?equi from a measured f0, for the case when placing antenna on material interface. One can further estimate the ground dielectric constant by using the equation: ?equi = (?air + ?ground )/2. Bow-tie antennas with different flange angles are constructed for experiments, in order to discuss the application of the above equation. The lengths of those antennas are all 30cm (length of the antenna conductor: 15cm). But the flange angles of the antenna conductors are respectively: 15, 40, 60, 75, 90 degrees. The antenna input reflections are measured over the frequency band up to 500 MHz, for cases when the antennas are placed in air and on sand, stone and water surfaces.

Paper Details

Date Published: 12 April 2002
PDF: 5 pages
Proc. SPIE 4758, Ninth International Conference on Ground Penetrating Radar, (12 April 2002); doi: 10.1117/12.462194
Show Author Affiliations
Fan-nian Kong, Norwegian Geotechnical Institute (Norway)

Published in SPIE Proceedings Vol. 4758:
Ninth International Conference on Ground Penetrating Radar
Steven Koppenjan; Hua Lee, Editor(s)

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