Further study on two-thickness-method for simultaneous measurement of complex EM parameters based on open-ended coaxial probe

Two-thickness-method (TTM) based on an open-ended coaxial probe is investigated in this paper with an emphasis on uncertainty analysis. Uncertainty equations in differential forms are established for the simultaneous measurement of complex electromagnetic (EM) parameters, i.e. permittivity ε and permeability μ, in the systematical consideration of all error factors in measurement. A numerical analysis is carried out to provide the relations between the uncertainties and test sample´s thicknesses via 3D figures, while the influence of the coaxial line´s dimension on the measurement accuracy is also included based on the same analysis method. The comparisons between the measured errors and theoretical uncertainty prediction are given for several samples, which validate the effectiveness of our analysis.