Radio Frequency Absorption-based Non-invasive Blood Glucose Monitoring: Development and Characterization of a Compact Antenna System

This work proposes a method of non-invasive blood glucose measurement based on the absorption properties of radio frequency signals as they pass through biological tissues. The core idea is that certain radio frequencies (RF) frequencies within the very high frequency (VHF) range interact differently with tissue depending on glucose concentration, altering signal strength in detectable ways. To investigate this, a series of experimental analysis are conducted on RF signal propagation throughout multiple mediums similar to human tissue indicating a particular frequency band which is sensitive to variations in glucose levels. Within this band, two resonant frequencies 156 MHz and 189 MHz are selected for in-depth study. In this context, a compact and low cost printed antenna is designed, simulated, fabricated, and characterized to operate efficiently at these frequencies. A measurement system, comprising transmitting and receiving antennas, records received signal strength (RSS) variations at the resonant frequencies, both with and without a fingertip present in the sensing region. Rather than using the raw signal strength values recorded during the investigation, a differential measurement approach is employed to enhance sensitivity and reliability. These variations in RSS are then compared with glucometer readings. The clinical trial includes eight volunteers whose participation provide the dataset used for evaluating system performance. A polynomial regression analysis shows moderate accuracy (R² = 0.5850). These results exhibit the potential of this non-invasive, RF-based method for continuous glucose monitoring. With further refinement, this technique could offer a practical, painless alternative to conventional invasive procedures that might completely transform diabetes control.