Exposure zones near parasitic elements in high powered antennas

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Title Exposure zones near parasitic elements in high powered antennas
Author Thiel, David Victor
Publication Title IEEE Antennas and Propagation Society International Symposium
Year Published 2008
Place of publication Piscataway USA
Publisher IEEE
Abstract This simple investigation, and results from many other experimental measurements and theoretical investigations demonstrate the following: a) There is a region close to the parasitic element where the electric field strength is greatly reduced and the magnetic field is greatly increased. b) The spatial rate of change of the field strength is very high. Small changes in distance can result in very large changes in electric field strength. This effect is observed in many transmitter situations. c) The presence of an additional conductor in this zone will influence the near fields and so can influence the overall effectiveness of the antenna. These conclusions are important because: a) Grounded towers used in VLF, LF and HF antennas show small regions where the measured and modeled quasi-static fields are greatly reduced. Such regions might be defined as “safe” when radiation exposure standards [6] are applied. b) The near field zone immediately behind Yagi-Uda antennas is not as “safe” as that predicted from far field to near field transform approximations (Ebersbach, Thiel and Leckenby [4]). c) Antenna isolation from nearby conductors using parasitic elements placed close to the driven elements is not particularly effective when compared to a large reflecting screen.
Peer Reviewed No
Published Yes
Publisher URI http://ieeexplore.ieee.org/servlet/opac?punumber=4604650
Alternative URI http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4618896&arnumber=4619003&count=1172&index=98
Copyright Statement Copyright 2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
ISBN 978-1-4244-2041-4
Conference name IEEE APS International Symposium
Location San Diego, CA USA
Date From 2008-07-05
Date To 2008-07-11
URI http://hdl.handle.net/10072/20620
Date Accessioned 2008-10-02
Language en_AU
Faculty Faculty of Science, Environment, Engineering and Technology
Subject PRE2009-Antenna Technology
Publication Type Conference Publications (Full Written Paper - Non-Refereed)
Publication Type Code e2

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