Complex Constitutive Parameter Extraction for Multilayered Samples using S-Parameter Waveguide Measurements

In this paper, a method was presented for accurately determining the complex CP from individual layers within a multilayer sample using S-parameter waveguide measurements. MPSQP, a modification of SQP, provided a simple mechanism to avoid local minima trapping while still obtaining the global minimum in a short amount of time. Comparison of the extracted CP to those of the SCL method showed that the MPSQP algorithm was successful in accurately estimating the CP for three single layer materials (one nonmagnetic and two radar absorbing). Results were also shown for a three layer material. Based on RMS error comparisons, the CP were found to be accurate to within the tolerance of the available measurements