A Noninvasive Method of Monitoring Blood Glucose Levels by Using Triple-Band Monopole Antenna

Abstract

This paper aims to present a novel methodology for noninvasive blood glucose monitoring. This method is based on monitoring the reflection coefficient of the proposed antenna-based sensor at three different bands simultaneously. This includes recording changes in the resonant frequency, magnitude, and phase. The above-mentioned parameters vary according to changes in blood conductivity and permittivity and consequently to blood glucose levels. A commercial FR4 substrate with compact dimensions of 30 × 40 × 1.6 mm³ is used to construct the proposed antenna, and all the simulations are conducted using 3D electromagnetic software. The proposed monopole is circular-shaped with an etched split ring resonator (SRR) to create multiband resonant frequencies. The proposed antenna measured the concentration of glucose level by using multiband resonant frequencies at 2.9, 4.3, and 6.5 GHz. The impedance bandwidth ≤ −10 dB is 1.038, 1.4, 2.02 GHz, respectively at each resonant frequency. To validate the operation of the proposed sensor, a container filled with samples representing different glucose concentrations is placed above the proposed sensor. To measure the blood glucose levels, a human finger phantom model is used with dimensions 15 × 12 × 10 mm³ in simulations. Moreover, glucose levels for four volunteers are compared in this paper before and after fasting using proposed sensors and a commercial glucometer. The proposed reflection-based microwave glucose sensing method exhibits an impressive sensitivity of 19.43 MHz/mg/dL.