A Novel Genetic Algorithm Based Method for Measuring Complex Permittivity of Thin Samples in the Compact Radar Frequency Band

The growing demand for novel smart and enabling metamaterial designs and semiconductor devices in health, energy, communication, and automatic industries requires designs of material with “thin” features. For broadband complex permittivity measurements using open-ended coaxial probe (OECP), thin sample measurements present significant challenges since a large amount of power may go through the sample making the measured reflection coefficient values unreliable. In this paper, a new approach for accurate measurement of thin material properties is developed. It employs genetic algorithm (GA) and full-wave numerical simulations to find the complex permittivity to match the measured reflection coefficients. The complex permittivity values for several thin samples of known materials are obtained using our approach. Challenges in measuring nanolayers of graphene samples will be described and an effective measurement approach will be discussed.