A resonant co-planar sensor at microwave frequencies for biomedical applications

This work presents a novel electromagnetic sensor operating at microwave frequencies for real-time evaluation of fluid properties, which has been designed with biomedical applications in mind. The sensor has a resonant co-planar type structure, which has been recently patented by the authors, along with a unique tuning feature that allows full control over the sensitivity and selectivity of the system response to different analytes by adjusting the resonant peak frequency and the corresponding quality factor at that frequency. The sensor operates based on the contactless interaction of the non-thermal intensity microwave signal with the solution of interest. By monitoring the changes in reflected and/or transmitted signals, usually expressed by S-parameters, the system provides for a solution to real-time fluid analysis. To evaluate the sensor feasibility for use in clinical settings, the work considers the sensitivity of the sensor to glucose dilutions near to physiological levels (10-100 mmol), and reports a calibration curve at 3.64 GHz to demonstrate this sensitivity. The sensor's stable and repeatable response suggest that it can serve as a long-awaited alternative to currently used time-consuming laboratory based methods of bodily fluid analysis.