Performance Analysis and Design Parameter Optimization of Resonance-Based Microwave Sensors for Material Characterization: A Review

This paper provides a critical review of many state-of-the-art split-ring resonator (SRR) and complementary split-ring resonator (CSRR) microwave sensors used for both solid and liquid sensing applications. A performance analysis is carried out through studying the effect of the variation in important design parameters, namely the resonator area, resonant frequency, resonator type (SRR or CSRR), number of rings/resonators, sample type (solid/liquid), sample size, and the sample location on a microwave sensor’s sensitivity and quality factor (Q-factor). The important observations drawn in this study will assist researchers and engineers in optimizing their selection of sensor design parameters (frequency, number of resonators, sample location, sample size) and type (SRR or CSRR) based on the required performance metrics (sensitivity and Q-factor) and material type (solid or liquid) for a given application. This usually helps much in obtaining more cost effective SRR or CSRR sensors with improved performance. The paper begins with a comprehensive and thorough review of microwave sensor theory, offering clear definitions and establishing a solid foundation of the most relevant parameters to ensure the clarity and rigor of the subsequent analysis and discussions.