Modeling of resistively loaded surface GPR antennas
Details
Serval ID
serval:BIB_8A0C11CC1653
Type
Inproceedings: an article in a conference proceedings.
Collection
Publications
Institution
Title
Modeling of resistively loaded surface GPR antennas
Title of the conference
Proceeding of the 10th International Conference on Ground Penetrating Radar, Delft, The Netherlands
ISBN
90-9017959-3
Publication state
Published
Issued date
2004
Volume
1
Pages
25-28
Language
english
Abstract
The design of surface ground-penetrating radar (GPR) antennas is inherently
difficult, primarily because the presence of the air-soil interface
greatly complicates both analytic and laboratory-based approaches
aimed at characterizing the antennas. Versatile numerical simulation
techniques capable of describing the key physical principles governing
GPR antenna radiation offer new solutions to this problem. We use
a finite-difference time-domain (FDTD) solution of Maxwell's equations
in 3-D Cartesian coordinates to explore the radiation characteristics
of various antennas operating in different environments. The antenna
panels are either modeled as perfect electrical conductors (PEC)
or as having a Wu-King-type conductivity profile. Input impedances,
radiated waveforms, and energy radiation patterns of antennas with
Wu-King conductivity profiles are largely invariant when placed in
free space or above half-space earth models. By comparison, antennas
with PEC panels have variable characteristics that depend on their
design and operating environment. Antennas with resistively loaded
panels are considerably less sensitive to their environment than
their PEC analogs, because the loss resistance is increased and the
effective electrical length of the antenna becomes shorter when the
antenna panels are resistively loaded. For Wu-King conductivity profiles,
the current in the antenna panels approaches that of a quasi-infinitesimal
electric dipole. Unfortunately, the favorable characteristics of
the Wu-King-type antennas are counter-balanced by markedly lower
radiation efficiency. We found that the peak energy radiated into
realistic earth models from antennas with Wu-King conductivity profiles
is about one order-of-magnitude lower than for PEC antennas.
difficult, primarily because the presence of the air-soil interface
greatly complicates both analytic and laboratory-based approaches
aimed at characterizing the antennas. Versatile numerical simulation
techniques capable of describing the key physical principles governing
GPR antenna radiation offer new solutions to this problem. We use
a finite-difference time-domain (FDTD) solution of Maxwell's equations
in 3-D Cartesian coordinates to explore the radiation characteristics
of various antennas operating in different environments. The antenna
panels are either modeled as perfect electrical conductors (PEC)
or as having a Wu-King-type conductivity profile. Input impedances,
radiated waveforms, and energy radiation patterns of antennas with
Wu-King conductivity profiles are largely invariant when placed in
free space or above half-space earth models. By comparison, antennas
with PEC panels have variable characteristics that depend on their
design and operating environment. Antennas with resistively loaded
panels are considerably less sensitive to their environment than
their PEC analogs, because the loss resistance is increased and the
effective electrical length of the antenna becomes shorter when the
antenna panels are resistively loaded. For Wu-King conductivity profiles,
the current in the antenna panels approaches that of a quasi-infinitesimal
electric dipole. Unfortunately, the favorable characteristics of
the Wu-King-type antennas are counter-balanced by markedly lower
radiation efficiency. We found that the peak energy radiated into
realistic earth models from antennas with Wu-King conductivity profiles
is about one order-of-magnitude lower than for PEC antennas.
Create date
25/11/2013 19:27
Last modification date
20/08/2019 15:48