Study and Design of a Dual-Cavity Differential Resonant Sensor for Small Liquid Samples

This paper presents the development and characterisation of a differential RF sensor specifically designed for the dielectric analysis of small liquid samples. The proposed sensor architecture comprises a microstrip line integrated with two identically-dimensioned split-ring resonators, engineered to achieve a resonance at 1.89 GHz when unloaded. Experimental measurements confirm the sensor's high sensitivity to the liquids under investigation and demonstrate its versatility, enabled by the incorporation of two dedicated cavities per resonator. Furthermore, the design's performance aligns with theoretical predictions, attesting its robust and reliable operation under various conditions.