Measurement of Complex Permittivity of Materials Using Electromagnetic Wave Propagation in Free Space and Super High-Resolution Algorithm

In this paper, we propose a model that can be used to estimate the complex permittivity of a material sample placed in free space using a super high-resolution algorithm. The measurement system consists of a transmitting and a receiving horn antennas, a network analyzer, and a computer. Operating in 8.0–12.0 GHz frequency range, it could be used to measure the transmission coefficient (S12 or S21) through the material sample. From the measured values of S12 or S21, the complex permittivity of the material is estimated by multiple signal classification (MUSIC) algorithm. The proposed method is verified for POM-C sample with different numbers of frequencies. The results show that the dielectric constant of POM-C sample is determined accurately when the number of frequencies is more than or equal to 201 in the frequency range of 8.0 GHz to 12.0 GHz.