Modified NRW algorithm for unmatched cell

A method for determining the complex permittivity and permeability of liquids in a unmatched coaxial cell is presented. This approach is an extension of the well known Nicolson-Ross-Weir (NRW) algorithm. A g-factor is introduced in the reflection coefficient to account for the cell impedance mismatch. Its value can be calculated from theory and adjusted by calibration. The focus of this work is to characterize liquids using transmission/reflection method, hence a broadband coaxial cell was development to operate in the 300 kHz to 3 GHz frequency range. Experimental results are presented to demonstrate the method with several liquid materials of known permittivity.