Combining Broad-Band Multisines Excitations and Dielectric Spectroscopy for Non-Invasive Glucose Measurements

A common non-invasive glucose measurement technique is based on dielectric spectroscopy (DS). This technique allows measuring the properties of the system as a function of the frequency as well as distinguishing between the different processes that could be involved. When developing a non-invasive glucose measurement system, one must deal with different noise sources that need to be identified and quantified in order to provide confidence bounds for the estimated glucose level. Hence advanced signal processing techniques are needed to quantify, detect and discriminate the presence of noise sources as well as the non-linear distortions inherent to the system. Combining non-linear identification techniques and odd random phase multisines (ORPM), together with the (DS) will allow for an accurate non-invasive glucose measurement system. Method and results: Results based on a matrix of glucose and blood-protein at different concentrations show the ability of the approach to differentiate the glucose levels in amplitude and phase with great precision, as well as the estimation of the noise level. Experiments using more complex matrices in an incremental experimentation (saline solution, serum, plasma and cells culture, complete blood and finally over the skin) can show the influence of the different blood-components and environmental factors over the glucose impedance measurement. Conclusions: The capabilities of a ORPM to perform glucose measurements are studied. The measurement technique is based on DS and uses a ORPM excitations signal analysis. Although the results are preliminary, they clearly elucidate the capabilities of random phase multisine analysis for glucose measurements.