Emerging EM wave sensors for non-invasive glucose monitoring: Review, techniques and developments

As a chronic disease, diabetes has impacted millions of individuals across the globe and is spreading at a very fast rate among adults mainly. Continuous observations of essential indicators like pulse rate, arterial pressure, and blood sugar levels, and oxygen saturation are crucial to maintain a healthy life and preventing severe complications associated with these. Using non-invasive method of blood glucose monitoring has paved its way to be one of the most prominent safest technique without harming the skin of the patients. This examination delves into the application of planar resonant sensors utilizing microwaves for quantifying glucose concentrations. The sensors based on RF EM waves mainly operating in the region from few MHz to GHz frequencies have garnered notable attention in the scientific community in recent years due to their significant contributions. They can detect alterations in dielectric properties caused by fluctuations in glucose concentrations. These sensors exhibit electrical reactions that rely on the dielectric properties of their surroundings. This review offers a current assessment of this sensing methodology, categorized by sensing parameters, and suggests typical non-invasive microwave sensor varieties for assessment. It further examines the key aspects of different sensor types, outlines potential future avenues, and addresses challenges in the field of glucose monitoring.