Frequency tunable non-invasive microwave blood glucose sensor based on negative impedance circuit

Abstract This article proposes a frequency adjustable non-invasive blood glucose microwave sensor based on negative impedance circuit. Firstly, this article establishes a skin-blood-skin human tissue model for the detection of non-invasive microwave sensors. Compared to traditional passive microwave blood glucose sensors, this design uses a negative impedance compensation circuit (NIC), greatly increasing microwave penetration and improving its detection sensitivity. In addition, this design achieves the goal of adjustable operating frequency by adding an additional dielectric layer at the detection end. This function is of great significance for microwave non-invasive blood glucose sensors. On the one hand, it can adjust to the optimal operating frequency band according to the characteristics of blood glucose changes; On the other hand, it is possible to measure changes in blood glucose concentration at multiple frequency points, thereby increasing the accuracy of detection. The relevant results show that adjusting the frequency band can reach 1–4 GHz, and the specific method of frequency adjustment is provided in the article; Meanwhile, four initial frequency points were selected in the article, at which the results show that the sensitivity reaches 1.356 × 10 −3 , 3.142 × 10 −3 , 2.071 × 10 −3 , 1.903 × 10 −3 . The above results demonstrate the superiority of our design, and blood glucose sensors based on this principle are expected to break through the limitations of current blood glucose sensors.