Highly Sensitive Miniaturized DS-CSRR Sensor for Complex Permittivity Measurements

This work presents the simulation study of a novel square Double Split Complementary Split Ring Resonator (DS-CSRR) resonating at 2470 MHz of the ISM band to be used as microwave-based planar resonator sensor for estimating the complex permittivity of unknown chemical samples. Polynomial curve fit equations were derived from the simulated data obtained using High Frequency Structure Simulator (HFSS). Using this dielectric constant (ε‘) and dielectric loss (ε”) of unknown liquid sample were determined. The developed fit equations are based on the performance of the sensing element for the six Liquid Under Tests (LUTs) spanning over 1–111 of permittivity values. The found average and normalized sensitivity of the proposed sensor are 42 MHz per unit dielectric constant and 1.7 respectively which is much higher in comparison to recently published works. The applicability of the sensor in material characterization can be assured as it can accurately predict the real and imaginary parts of complex permittivity of unknown sample with less than 3.4% difference.