Microwave substrate integrated waveguide resonator sensor for non-invasive monitoring of blood glucose concentration: Low cost and painless tool for diabetics

In this study, a microwave resonant sensor with an operation frequency of 9 GHz and a quality factor of 240 has been designed, fabricated and tested by fingertips of the users to control blood glucose levels. The proposed method includes the implementation of a band-pass filter in the substrate integrated waveguide cavity, which has been carried out using a modified split ring resonator. In this research, 4 volunteers with glucose level changes ranging from 92 to 141 mg dL−1 have been tested invasive (by a glucometer) and non-invasive (by the designed sensor). For this range of glucose level changes, the frequency detection resolution is 7.67 MHz (mg dL−1)−1.