Wideband extraction of soil dielectric spectrum from vector-network-analyzer measurements

We present a methodology for soil relative-dielectric-permittivity characterization in the 0.001-3 GHz frequency range. Our approach relies on a vector-network-analyzer scatteringparameter measurement of a soil sample placed into a 1 5/8” coaxial transmission line. In order to calibrate the vector-network-analyzer we use a new calibration technique which combines the multiline through-reflect-line and through-reflect-match schemes, and therefore overcomes the inherent low-frequency limitation of the multiline through-reflect-line approach. We determine the relative dielectric permittivity from sample scattering-parameters by use of a new multi-frequency extraction algorithm which overcomes the low-frequency inaccuracies of non-iterative approaches. Experimental results for soil samples with different moisture content and salinity confirm the validity of our methodology.