Feasibility Evaluation of Metamaterial Microwave Sensors for Non-Invasive Blood Glucose Monitoring

Abstract

The use of microwave technology is currently under investigation for non-invasive estimation of glycemia in patients with diabetes. Due to their construction, metamaterial (MTM)-based sensors have the potential to provide higher sensitivity of the phase shift of the S21 parameter (∠S21) to changes in glucose concentration compared to standard microstrip transmission line (MSTL)-based sensors. In this study, a MSTL sensor and three MTM sensors with 5, 7, and 9 MTM unit cells are exposed to liquid phantoms with different dielectric properties mimicking a change in blood glucose concentration from 0 to 14 mmol/L. Numerical models were created for the individual experiments, and the calculated S-parameters show good agreement with experimental results, expressed by the maximum relative error of 8.89% and 0.96% at a frequency of 1.99 GHz for MSTL and MTM sensor with nine unit cells, respectively. MTM sensors with an increasing number of cells show higher sensitivity of 0.62° per mmol/L and unit cell to blood glucose concentration as measured by changes in ∠S21. In accordance with the numerical simulations, the MTM sensor with nine unit cells showed the highest sensitivity of the sensors proposed by us, with an average of 3.66° per mmol/L at a frequency of 1.99 GHz, compared to only 0.48° per mmol/L for the MSTL sensor. The multi-cell MTM sensor has the potential to proceed with evaluation of human blood samples.

Research Progress on Biomimetic Nanomaterials for Electrochemical Glucose Sensors

“…In recent years, diabetes has become an epidemic with a high incidence [ 1 ]. The blood glucose level of normal people ranges from 4.4 to 6.6 mmol L −1 .…”

Noninvasive Method for Measuring the Blood Glucose Level Using a Narrow Band Microstrip Antenna

“…However, when it comes to testing blood sugar levels, various options are discussed [6][7][8][9][10][11][12]. Furthermore, several innovative microwave sensors were presented by Lukas in [13], and another pressure sensor was proposed by Satish in [14]. A technique for determining glucose levels was developed by Deshmukh, and Ghongade, who used a ring resonator to calculate the dielectric properties and estimate the glucose levels [15].…”

A High Precision and Multifunctional Electro-Optical Conversion Efficiency Measurement System for Metamaterial-Based Thermal Emitters

“…Infrared, thermal-emitter-based, layered metamaterials (LMMs) have many advantages over traditional emitters [ 1 , 2 , 3 ], such as adjustable wavelengths, low visible-light emission, and high efficiency. This type of emitter has broad applications in infrared monitoring [ 4 ], gas sensing [ 5 ], and radiation cooling [ 6 ], and is the research hot-spot in the energy [ 7 , 8 , 9 ] and sensing fields [ 10 , 11 , 12 ]. Light emission-correlated tests for LMM are usually performed on bulky external heaters [ 1 , 13 , 14 ].…”