Feasibility Study of Glucose Concentration Measurement of Aqueous Solution Using Time Domain Reflected Signals

Area of Science:

• Applied Physics
• Spectroscopy
• Biomedical Engineering

Background:

• Wideband microwave spectroscopy (WBMS) is utilized for material characterization.
• Traditional blood glucose sensing via microwave spectroscopy often employs resonant frequency-domain methods.
• Time-domain (TD) WBMS presents a cost-effective and accessible alternative for glucose sensing in aqueous solutions.

Purpose of the Study:

• To present early research on implementing a TD dielectric spectroscopy setup for glucose concentration measurement.
• To compare frequency-domain (FD) and TD methods for glucose sensing.
• To establish a relationship between TD reflected signals and glucose concentration.

Main Methods:

• Utilized a quasi-monostatic setup for measurements between 0.1 to 6 GHz.
• Calculated TD reflected signals from water with varying glucose content using inverse Laplace transform.
• Employed Vector Network Analyzer (VNA) with Vivaldi antennas for FD measurements and a maximum length sequence (m-sequence) transceiver for direct TD measurements.

Main Results:

• Measurement and numerical results showed good agreement, following the same trend.
• A monotonic relationship was observed between the peaks of TD signals and glucose concentration.
• The variation in reflected signal peak height was 0.00002 for FD and 0.0005 for direct TD measurements per 50 mg/dL glucose concentration.

Conclusions:

• The developed TD dielectric spectroscopy setup is effective for glucose concentration measurement.
• TD WBMS provides a viable and convenient method for blood glucose sensing.
• The study investigated glucose concentrations from 25 mg/dL to 400 mg/dL with a worst-case repeatability of 3.65%.