The permittivity and the conductivity of the ground surface may be obtained by measuring the transfer parameters between two loop antennas in the ground interface by using the network analyzer.
The electromagnetic fields in the interface between the air and the ground medium due to a vertical magnetic dipole in the interface is given in closed form. By taking the ratio between the transfer scattering parameters, ＄S_{21}({\rho1})/S_{21}({\rho_2})＄, at two distances $\rho_1$ and $\rho_2$, one may obtain the complex wave number of the ground and hence calculate the permittivity and the conductivity of the ground which is insensitive of the antenna characteristics at different frequencies.
In situ measured relative dielectric constant and conductivity of the ground yields 20 to 6 and 0.04 to 0.02 S/m respectively, depending on the frequencies from 55MHz to 95MHz. The measurement accuracy is tested by measuring the relative permittivity and the conductivity of the air in the anechoic chamber by using the same loop antennas and the network analyzer in the frequency ranges from 200MHz to 600MHz.
