Self-Calibrating Transmission-Reflection Technique for Constitutive Parameters Retrieval of Materials

A self-calibrating transmission-reflection method for extraction of electromagnetic properties of materials from waveguide measurements is proposed. It relies on three measurement steps (thru, empty line, and the same line loaded at any position by the sample) to extract electromagnetic properties. When compared with other nonresonant transmission-reflection methods, it has the following features: 1) it does not require application of any calibration method; 2) it does not need any knowledge of the position of the sample within its cell (position invariant); 3) it determines constitutive parameters of the sample; 4) it is noniterative; and 5) it does not involve any sign ambiguity in determination of constitutive parameters. The method was validated and its accuracy was compared with the accuracy of other methods from measured uncalibrated and calibrated scattering parameters of the polyethylene sample with different lengths (3.85 and 7.70 mm). We also applied our method for extraction of electromagnetic properties of a synthesized magnetic sample from its simulated scattering parameters by using the CST Microwave Studio. Following measurements, simulations, and validation, repeatability and uncertainty analyses were performed to access and improve the accuracy of the proposed method.