A novel constitutive parameter extraction technique using a single short circuit waveguide measurement

In this paper, a method was presented for accurately determining the complex CP of a material sample using a single SCL waveguide measurement. An analytic expression for the complex reflection coefficient at the reference plane of the waveguide serves as the forward problem in the novel MPSQP algorithm. The MPSQP is a very robust optimization technique which exploits the speed and accuracy of SQP while avoiding local minima trapping. This technique proves beneficial for several application areas including high temperature material characterization. At high temperatures, a considerable amount of time is devoted to changing terminations, and this process usually requires some amount of cooling and reheating of the sample. During this time, the sample may shift inside the waveguide which, in turn, may introduce errors into the measured data