Topology optimization-based design of metamaterial-inspired sensor with improved sensitivity

Sensitivity is of great importance for a Metamaterial (MTM)-inspired sensor in many detecting and sensing applications. In this paper, a new improved sensitivity method for a metamaterial-inspired sensor is proposed, which is based on MTM microstructure topology optimization. The metamaterial-inspired sensor consists of a microstrip-lined excitation and a coupled MTM microstructure, and can be used to dielectric sensing by tracking the resonant frequency shift. The optimization model is established to improve the sensitivity of the sensor where the MTM microstructure is topologically optimized in the design domain. To validate the improved sensitivity, a sensor is designed to monitor the dielectric film thickness. Compared with the complementary split ring resonator (CSRR), complementary single split ring resonator (CSSRR) based sensors, the novel sensor with an optimized MTM exhibits more frequency shift for a tiny variation of the dielectric thickness. The relationship between the dielectric thickness and the resonant frequency is established through polynomial interpolation fitting.