Extraction of Complex Permittivity and Complex Permeability of Liquids by Using a Grounded Coplanar Waveguide with Upper Shielding

This paper proposes a method for extracting the complex permittivity and complex permeability of liquid ma-terials, utilizing sensing structure based on a grounded copla-nar waveguide with upper shielding (GCPWG) and a genetic algorithm (GA). The scattering (S-)parameters of the GCPWG sensing area that is loaded with the material under test (MUT) are obtained through simulation in the CST Studio Suite. Then, the GA optimization procedure of High Frequency Simulator Structure (HFSS) is utilized to minimize the difference between the simulated S-parameters form CST and HFSS. By iteratively searching for the optimal values, the complex permittivity and complex permeability of MUT can be obtained. The method is applicable for extracting the dielectric and magnetic properties of both non-dispersive and frequency-dispersive materials over a broadband frequency range. For validation, four non-dispersive materials and a water based mimic solution, as a frequency dependent dispersive material, are analyzed, by using the S-parameters obtained from the full-wave electromagnetic simulation methods over a frequency range from 5 GHz to 15 GHz.