1887
Volume 11 Number 2
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

ABSTRACT

In this study, we numerically evaluated a full‐wave antenna model for near‐field conditions using a Finite‐Difference Time‐Domain (FDTD) antenna model. The antenna is effectively characterized by a series of source and field points and global reflection/transmission coefficients, which by using analytical solutions of Maxwell’s equations, enable us to significantly reduce computation times compared to numerical approaches. The full‐wave GPR model was calibrated by a series of radar data from numerical measurements performed above an infinite perfect electrical conductor (PEC). The calibration results provided a very good agreement with data from the FDTD antenna model giving a correlation coefficient of 0.9995. The model was subsequently verified by using it to invert responses from the FDTD antenna model to reconstruct the electrical properties of an artificial medium subject to 8 scenarios of layering, thickness and electrical properties. Full‐wave inverse modelling enabled us to very well reproduce the GPR data both in time and frequency domains, resulting in accurate estimations of the dielectric permittivity even with a two‐layered medium with highly contrasting electrical properties. The relative errors of the permittivity estimation were less than 5% for all medium scenarios and antenna heights. Inversion also provided very good estimations of the electrical conductivity when this parameter was relatively high but poor results were obtained for low conductivities. Surface response analysis showed that the model was more sensitive to permittivity than conductivity and more sensitive to high than low conductivities. Our modelling approach shows great potential to apply full‐wave inversion for retrieving the electrical properties of the subsurface from near‐ and far‐field radar measurements.

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2012-10-01
2020-09-20
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References

  1. AtteiaG.E. and HusseinK.F.A.2010. Realistic model of dispersive soils using PLRC‐FDTD with applications to GPR systems. Progress in Electromagnetics Research B26, 335–359.
    [Google Scholar]
  2. ChenH.‐W. and HuangT.‐M.1998. Finite‐difference time‐domain simulation of GPR data. Journal of Applied Geophysics40, 139–163.
    [Google Scholar]
  3. ChenS.H.Y., YangS. and NieZ.2010. Fast analysis of microstrip antennas over a frequency band using an accurate MoM matrix interpolation technique. Progress in Electromagnetics Research109, 301–324.
    [Google Scholar]
  4. ChewW.C.1995. Weaves and Fields in Inhomogeneous Media. Van Nostrand Reinhold.
    [Google Scholar]
  5. CraeyeC., TijhuisA.G. and SchaubertD.H.2004. An efficient MoM formulation for finite‐by‐infinite arrays of two‐dimensional antennas arranged in a three‐dimensional structure. IEEE Iransactions on Antennas and Propagation52, 271–282.
    [Google Scholar]
  6. DurandS. and SlodickaM.2011. Fully discrete finite element method for Maxwell's equations with nonlinear conductivity. IMA Journal of Numerical Analysis, 31(4).
    [Google Scholar]
  7. ErnstJ.R., MaurerH., GreenA.G. and HolligerK.2007. Full‐waveform inversion of crosshole radar data based on 2‐D finite‐difference time‐domain solutions of Maxwell's equations. IEEE Transactions on Geoscience and Remote Sensing45, 2807–2828.
    [Google Scholar]
  8. FarnooshN., ShooryA., MoiniR. and SadeghiS.H.H.2008. Analysis of thin‐wire ground penetrating radar systems for buried target detection, using a hybrid MoM‐FDTD technique. NDT & E International41, 265–272.
    [Google Scholar]
  9. Fernndez PantojaM., YarovoyA.G., Rubio BretonesA. and Gonzlez GarcaS.2009. Time domain analysis of thin‐wire antennas over lossy ground using the reflection‐coefficient approximation. Radio Science44.
    [Google Scholar]
  10. GalagedaraL.W., RedmanJ.D., ParkinG.W., AnnanA.P. and EndresA.L.2005. Numerical modeling of GPR to determine the direct ground wave sampling depth. Vadose Zone Journal4, 1096–1106.
    [Google Scholar]
  11. GentiliG.G. and SpagnoliniU.2000. Electromagnetic inversion in monostatic ground penetrating radar: TEM horn calibration and application. IEEE Transactions on Geoscience and Remote Sensing38, 1936–1946.
    [Google Scholar]
  12. GhasemiF.S.A. and AbrishamianM.S.2007. A novel method for FDTD numerical GPR imaging of arbitrary shapes based on Fourier transform. NDT & E International40, 140–146.
    [Google Scholar]
  13. GiannopoulosA.2005. Modelling ground penetrating radar by GprMax. Construction and Building Materials19, 755–762.
    [Google Scholar]
  14. HarutyunyanD.2007. Adaptive vector finite element methods for the maxwell equations. PhD dissertation.
    [Google Scholar]
  15. HuangZ.B., DemarestK.R. and PlumbR.G.1999. An FDTD/MoM hybrid technique for modeling complex antennas in the presence of heterogeneous grounds. IEEE Transactions on Geoscience and Remote Sensing37, 2692–2698.
    [Google Scholar]
  16. HuyerW. and NeumaierA.1999. Global optimization by multilevel coordinate search. Journal of Global Optimization14, 331–355.
    [Google Scholar]
  17. JadoonK., LambotS., SlobE. and VereeckenH.2008. Uniqueness and stability analysis of hydrogeophysical inversion for time‐lapse proximal ground penetrating radar. Water Resources Research44, W09421.
    [Google Scholar]
  18. LambotS.2012. Method and device for characterization of physical properties of a target volume by electromagnetic inspection. European Patent Office, Patent Application N° PCT/EP2012/055416, 2012–0401.
    [Google Scholar]
  19. LambotS. and AndréF.2012. Full‐waveform modelling of near‐field radar data to reconstruct planar layered media. IEEE Transactions on Geoscience and Remote Sensing, in press.
    [Google Scholar]
  20. LambotS., AntoineM., VancloosterM. and SlobE.C.2006. Effect of soil roughness on the inversion of off‐ground monostatic GPR signal for noninvasive quantification of soil properties. Water Resources Research42, W03403.
    [Google Scholar]
  21. LambotS., JavauxM., HupetF. and VancloosterM.2002. A global multilevel coordinate search procedure for estimating the unsaturated soil hydraulic properties. Water Resources Research38(11), 1224.
    [Google Scholar]
  22. LambotS., SlobE.C., van den BoschI., StockbroeckxB. and VancloosterM.2004. Modeling of ground‐penetrating radar for accurate characterization of subsurface electric properties. IEEE Transactions on Geoscience and Remote Sensing42, 2555–2568.
    [Google Scholar]
  23. LambotS., SlobE. and VereeckenH.2007. Fast evaluation of zero‐offset Green's function for layered media with application to ground‐penetrating radar. Geophysical Research Letters34, 1–6.
    [Google Scholar]
  24. LambotS., TranA.P. and AndreF.2012. Near‐field modeling of radar antennas for wave propagation in layered media: When models represent reality. 14th International Conference on Ground Penetrating Radar (GPR), 42–46.
    [Google Scholar]
  25. LoperaO., MilisavljevićN. and LambotS.2007. Clutter reduction in GPR measurements for detecting shallow buried landmines: A Colombian case study. Near Surface Geophysics5(1), 57–64.
    [Google Scholar]
  26. MichalskiK.A. and MosigJ.R.1997. Multilayered media Green's functions in integral equation formulations. IEEE Transactions on Antennas and Propagation45, 508–519.
    [Google Scholar]
  27. MinetJ., WahyudiA., BogaertP., VancloosterM. and LambotS.2012. Mapping shallow soil moisture profiles at the field scale using full‐waveform inversion of ground penetrating radar data. Geoderma161, 225–237.
    [Google Scholar]
  28. SlobE. and FokkemaJ.2002. Coupling effects of two electric dipoles on an interface. Radio Science37, 1073–1082.
    [Google Scholar]
  29. WarrenC. and GiannopoulosA.2011. Creating finite‐difference time‐domain models of commercial ground‐penetrating radar antennas using Taguchi's optimization method. Geophysics76, G37–G47.
    [Google Scholar]
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