Frequency Characterization for Glucose Detection with Software Defined Radio

An in-vitro study for non-invasive glucose detection using the method of electromagnetic (microwave) sensing is conducted using the programmable and tunable software-defined radio (SDR). The study determines the frequency or a range of frequency that is found to exhibit the highest correlation with different glucose concentration. The transmitted frequency range varies between 700 MHz to 6 GHz. When the transmitted base-band signal from the SDR is modulated at a specific carrier frequency and is allowed to pass through a glucose solution, the receiver end of the SDR detects the power level at the base-band power spectrum. It has been observed at center frequencies below 2.4 GHz, the power level is highly linear with glucose concentration. Specifically, the highest correlation is observed at a frequency of 1.7 GHz at which the application of simple linear regression led to R-squared coefficients of 91%. So far, to our knowledge there has been no such systematic study on frequency characterization to determine the frequency that has the highest correlation of power level with variation in glucose concentration.