HAL Id: hal-01615542
https://hal.archives-ouvertes.fr/hal-01615542
Submitted on 12 Oct 2017
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Numerical study of the polarization effect of GPR
systems on the detection of buried objects
Florence Sagnard
To cite this version:
Florence Sagnard. Numerical study of the polarization effect of GPR systems on the detection of
buried objects. EGU - European Geosciences Union General Assembly 2017, Apr 2017, Vienna,
Austria. EGU - European Geosciences Union General Assembly 2017, 1p, 2017. �hal-01615542�
www.
ifsttar
.fr
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Context
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Polarization is a fundamental property of propagation of electromagnetic waves
that provides a unique opportunity for
producing improved images of buried objects. It helps to discriminate different classes of objects and to estimate
parameters such as
the size, shape, orientation, and electrical properties of buried objects
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The definition of the GPR system
and particularly the antenna geometry and the frequency band (UWB) contribute to
provide images where information appears more accessible before applying pre-treatments
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Numerical simulations (FDTD and FIT)
appear essential
to study the polarization effects by means of a parametric study
Simulation senarios (50 MHz-4 GHz)
Conclusion
Numerical study of the polarization effect of GPR
systems on the detection of buried objects
F. Sagnard
LEOST, COSYS, University Lille Nord de France, Villeneuve d’Ascq, France
florence.sagnard@ifsttar.fr
Sub-surface probing using GPR
Bowtie slot antenna
190.4 mm
332.2
m
m
67 mm
313
m
m
TM polarization
TE polarization
Cross polarization
air
dielectric e’=12
soil e’=5.5
s=0,01 S/m
Buried pipes
Buried pipes in trenches
Case 1
Case 2
Case 3
225 mm
250
m
m
165 mm
210
m
m
124.8
m
m
40 mm
Case 4
Leaf antenna : a novel compact antenna geometry
dielectric e’=12
Case 1 (TM)
e’=1
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500
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Case 2 (TE)
e’=7
e’=1
e’=12
Radargrams
air-filled
pipe
pipe
eps=12
2,2 ns
direct
wave
without object
0,8 ns
Case 3 (TM-TE)
e’=12
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3,7 ns
4,3 ns
air-filled
pipe
pipe
eps=12
Case 4 (TM)
-200
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distance [mm]
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frequency [MHz]
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1
1
[
d
B
]
CST
(lossy Copper)
CST
(PEC)
EMPIRE
(PEC)
CST
(ovale ground
plane, PEC)
S11 in air (non shielded)
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frequency [MHz]
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1
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[
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S11 in air (bowtie-slot)
CST
(non shielded)
CST
(shielded)
S11/S21 on soil (
e’=5,5)
S11
S21
Config. n°2
Config. n°1
pipe
eps=12
air-filled
pipe
-200
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distance [mm]
tim
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0.02
Case 4 (TM-TE)
e’=1
Disymetry observed for cross-polarized antennas
Object responses depending on the polarization to be superimposed and compared
Effect of the antenna geometry on the direct coupling in the several polarization configurations
A parameter study to consider :
- Influence of the antenna geometry on polarization
- Contribution of the polarization to reduce the direct coupling and to improve the detection of shallow objects
- Pre-processing techniques to benefit from several components of polarization
- Quantify dielectric characteristics of buried objects
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