Coplanar Waveguide Transmission Line Loaded With Electric-LC Resonator for Determination of Glucose Concentration Sensing

In this paper, a compact glucose concentration sensor is designed based on an electric-LC (ELC) resonator coupled with a coplanar waveguide (CPW) transmission line, and the ELC resonator is no longer aligned with the CPW transmission line axis. The principle of the sensor is based on the notch depth in the transmission coefficient (S-21) depending on the glucose concentration, and it is applied using a micropipette into a cylindrical plastic sample chamber that covers the gap in the middle branch of the ELC resonator. The notch magnitude in the transmission coefficient response behavior was measured and analyzed in the range of 2.5-6 GHz with air, deionized water, phosphate buffered saline (PBS), and different glucose concentrations in deionized water and PBS in the range of 0%-20% (w/V). The experimental results showed that the proposed sensor has good detection of the glucose concentration with high linearity and wide dynamic range. A prototype of the sensor provides an opportunity for the development of a biological and chemical sensing application in the future.