Characterization of the complex permittivity of glucose/water solutions for noninvasive RF/Microwave blood glucose sensing

Simulating the Effects of Skin Thickness and Fingerprints to Highlight Problems With Non-Invasive RF Blood Glucose Sensing From Fingertips

“…A standard deviation of 230 kHz was observed between simulations which shows that the random voxel generation offers good repeatability. The blood voxels can be replaced with glucose/water Cole-Cole permittivity relaxation model [20] to investigate the effect of glucose concentration on the frequency response. As it can be seen from Fig.…”

“…This change causes a frequency shift in the sensor's frequency response. However, detecting this change is challenging as the expected frequency shift is less than 8 MHz for the realistic BGL range and error sources such as the make-up of the fingertip, its positioning and the pressure applied onto the sensor dominate the shift in the frequency response [20][21][22]. Hence, these factors were studied in detail to observe their effects and propose novel solutions.…”

Permittivity extraction of glucose solutions through artificial neural networks and non-invasive microwave glucose sensing

“…Hence, an accurate model for the complex permittivity of aqueous solutions of glucose is essential. A model was proposed by the authors in [10,11], which was then extended in this work. Moreover, the reasoning behind the selection of design parameters e.g.…”

A novel pressure sensing circuit for non-invasive RF/microwave blood glucose sensors

“…Our experiments with our proposed sensor showed that a measurement with a fingertip is extremely sensitive to the pressure applied. The frequency difference in the resonant peaks between a light and a firm pressure on the sensor may be as high as 240 MHz whereas the expected shift due to blood glucose variation is well under 10 MHz [7]. This shows that if the pressure is not monitored precisely, the shift due to glucose variation will be masked under the shift resulting from the pressure variation causing measurement error.…”

“…A compact non-invasive RF glucose sensor was designed, fabricated and used in this study [7]. The designed sensor is based on a one-port microwave resonator, which acts as an antenna used for near-field radiation.…”