A Stepwise Nicolson–Ross–Weir-Based Material Parameter Extraction Method

Approaches of automated evaluation of electromagnetic material parameters have received a lot of attention in the literature. Among others, one method is to retrieve the material parameters from the reflection and transmission measurements of the sample material. Compared to other methods, this is a rather wideband method, but suffers from an intrinsic limitation related to the electrical thickness of the measured material. In this letter, we propose a novel way to overcome this limitation. Although being based on the classical Nicolson–Ross–Weir (NRW) technique, the proposed extraction technique does not involve any branch seeking and is therefore capable of extracting material parameters from samples thicker than
$\lambda/2$
, a measure that would otherwise cause problems in the NRW extraction technique. The proposed derivative of the NRW extraction technique is then used to study the effect of thermal noise on the extracted material parameters.