Low-Cost Electronics for Automatic Classification and Permittivity Estimation of Glycerin Solutions Using a Dielectric Resonator Sensor and Machine Learning Techniques

Abstract

Glycerin is a versatile organic molecule widely used in the pharmaceutical, food, and cosmetic industries, but it also has a central role in biodiesel refining. This research proposes a dielectric resonator (DR) sensor with a small cavity to classify glycerin solutions. A commercial VNA and a novel low-cost portable electronic reader were tested and compared to evaluate the sensor performance. Within a relative permittivity range of 1 to 78.3, measurements of air and nine distinct glycerin concentrations were taken. Both devices achieved excellent accuracy (98–100%) using Principal Component Analysis (PCA) and Support Vector Machine (SVM). In addition, permittivity estimation using Support Vector Regressor (SVR) achieved low RMSE values, around 0.6 for the VNA dataset and between 1.2 for the electronic reader. These findings prove that low-cost electronics can match the results of commercial instrumentation using machine learning techniques.

New Complementary Resonator for Permittivity- and Thickness-Based Dielectric Characterization

“…The properties of metamaterial structures can be controlled by adjusting their geometrical parameters, such as shape, size, and periodicity. This adaptability permits customization of frequency and application-specific responses [3]. Split ring resonators (SRR) [4] and complementary split ring resonators (CSRR) [5] are utilized extensively in numerous metamaterial-based microwave sensors and devices, such as filters [6], antennas [7], absorbers [8], and radars [9].…”