A Microwave Biosensor for Non-invasive Blood Glucose Detection with Accuracy Enhancement

In this paper, a non-invasive microwave sensor based on a metamaterial structure is proposed to monitor the change of blood glucose concentration on human body. Especially, the nonlinear characteristics of the PIN diode are introduced to increase the frequency shift, and to improve the detection accuracy of the blood glucose concentration (BGC). In this simulation, blood glucose concentrations with dielectric constants of 49.6 and 51.6 were selected for simulation. In the case where the PIN diode is not loaded, the frequency variation (Δf) is 1.4MHz and the magnitude of S₁₁(ΔS₁₁) is 0.7dB. In the case of loading a PIN diode, the Δf is 5.2MHz and ΔS₁₁ is 1.2dB. The improvements of Δf and ΔS₁₁ indicates that with nonlinear effects, a weaker change in blood glucose concentration can be detected, thereby achieving the purpose of improving detection accuracy.