High Accuracy Split Ring Resonator Based Sensor with Polynomial-Assisted Dielectric Characterization for Solid Material

Abstract

These days, the measurement of electromagnetic material properties has gained significant attention due to its important role in microwave sensing and material characterization applications. Although conventional techniques provide high measurement accuracy, many existing sensors still suffer from large physical size, high fabrication cost, and complex structures. To address these limitations, a compact split ring resonator (SRR)-based sensor was developed for accurate dielectric characterization. The proposed sensor operates at a stable resonant frequency of 3.854 GHz and utilizes multiple offset resonant frequencies combined with polynomial fitting analysis to improve dielectric constant extraction accuracy. Experimental validation using Rogers 5880, Rogers 4350, and FR4 substrates demonstrates dielectric constant accuracies of 98.67%, 88.36%, and 97.14%, respectively, while loss tangent accuracy exceeds 99% for all tested materials. The optimized 12mm x 12mm sensor on FR4 also provides stable resonance response, low loss and high Q-factor, making it suitable for low-cost and reliable microwave sensing applications.