A robust optimization algorithm for the reconstruction of dielectric properties of lossy composite materials

A novel optimization algorithm is presented to determine the relative permittivity and conductivity of composite materials from the measurement of reflection and transmission data. The reflection and transmission coefficients of the material-under-test (MUT) are measured with the help of a vector network analyzer, by placing the MUT precisely into a section of WR-340 waveguide. The reconstruction of the dielectric properties is achieved by computing the scattering parameters of the MUT with the help of a transmission line approach, and then minimizing the error between the computed and the measured scattering data using the proposed algorithm.