Feasibility of non-invasive blood glucose monitoring: In-vitro measurements and phantom models

The objective of the present work is to demonstrate the feasibility of non-invasively monitoring blood glucose levels. The technique is based on relating a monitoring antenna´s resonant frequency to the permittivity and conductivity of blood which in turn is related to the glucose levels. At first a realistic data base for the dielectric properties of blood was established through in-vitro measurements performed on blood samples obtained from 10 patients with glucose levels ranging from normal (87 mg/dl) to hyperglycemic (330 mg/dl). Using the Agilent 85070E dielectric probe and an Agilent 8720B network analyzer the dielectric permittivity and conductivity of the blood samples were measured over a frequency range of 1GHz - 10GHz. The resonant frequency of a wideband antenna strapped to the patient was monitored as the patient ingested fast acting glucose tablets. It has been noted that the antenna resonant frequency increases as the glucose level increases. Blood phantom models have been built to replicate in-vitro measurements and the shift in the resonant frequency has been demonstrated. The work in progress is the development of an analytical model to relate the antenna response to the glucose level.