Exposure zones near parasitic elements in high powered antennas

Loading...
Thumbnail Image
File version
Author(s)
Thiel, David V
Griffith University Author(s)
Primary Supervisor
Other Supervisors
Editor(s)
Date
2008
Size

379638 bytes

File type(s)

application/pdf

Location

San Diego, CA

License
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.

Journal Title
Conference Title

2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9

Book Title
Edition
Volume
Issue
Thesis Type
Degree Program
School
Publisher link
Patent number
Funder(s)
Grant identifier(s)
Rights Statement
Rights Statement

© 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.

Item Access Status
Note
Access the data
Related item(s)
Subject
Persistent link to this record
Citation