Soils can be characterised by measuring and analysing dielectric properties. The coaxial transmission line measurement is the cost common technique to measure complex permittivity in a wide frequency range. Authors developed a new method for inverting measured data and retrieving complex permittivity. The method numerically models the measurement setup by finite difference time domain (FDTD) method and updates the model to minimise the error between the modelling and measurements. The developed method was tested with standard materials: air, water and ethanol, and showed that it does not have issues of the conventional method, which is based on the analytical solution. Further, complex permittivity of sand was measured and inverted by the developed method. The results show the clear difference depending on various water contents.


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  1. Baker-Jarvis, J., Vanzura, E.J. and Kissick, W.A.
    [1990] Improved technique for determining complex permittivity with the transmission/reflection method. IEEE Trans. Microwave Theory and Tech., 38(8), 1096–1103.
    [Google Scholar]
  2. Nelder, J.A. and Mead, R.
    [1965] A simplex method for function minimization. The Computer Journal, 7(4), 308–313.
    [Google Scholar]
  3. Nicolson, A.M. and Ross, G.F.
    [1970] Measurement of the intrinsic properties of materials by time-domain techniques. IEEE Trans. Inst. Meas., 19(4), 377–382.
    [Google Scholar]
  4. Takahashi, K., Loewer, M., Igel, J. and Konishi, C.
    [2018] Determination of complex permittivity by inverting coaxial transmission line data using FDTD. In: Proc. Int. Conf. GPR, 2018. 495–500.
    [Google Scholar]
  5. Topp, G.C., Davis, J.L. and Annan, A.P.
    [1980] Electromagnetic determination of soil water content: measurements in coaxial transmission lines. Water Resource Research, 16, 574–582.
    [Google Scholar]
  6. Weir, W.B.
    [1974] Automatic measurement of complex dielectric constant and permeability at microwave frequencies. Proc. IEEE, 62(1), 33–36.
    [Google Scholar]

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