Extraction of permittivity and permeability of low-loss fluids taking into account the impedance-mismatch and calibration reference-plane position

An improved Nicolson-Ross-Weir (NRW) algorithm is obtained by incorporating an impedance-mismatch factor and reference-plane-correction factors into the equations. Impedance mismatch and reference plane position are sources of error in the extraction of the permittivity and permeability of low-loss fluids. To apply the algorithm, a detailed model of the coaxial cell is developed for the calculation of the full scattering equations. The new model fits experimental data and reduces to the model commonly found in the literature for such cells. Measurements and simulations were carried out in the 300 kHz to 3 GHz frequency range.