A Permittivity Measurement Sensor Based on Ridge Substrate-Integrated Waveguide

In this paper, a novel ridge substrate-integrated waveguide (RSIW) sensor is proposed, and the RSIW is optimized and simulated using full-wave simulation. A RSIW-based system was developed for measuring the permittivity of substances, and a neural network algorithm was utilized to reconstruct the permittivity in real time. The system was employed to measure the permittivity of mixed solutions of ethanol and deionized water, and the results were consistent with those obtained using a Keysight commercial probe. The relative errors of the real part and loss tangent were found to be less than 3% and 5%, respectively. These results indicate that the RSIW measuring apparatus is capable of accurate real-time measurement of the permittivity of materials. The simplicity of the manufacturing process, the reduced quantity of measurement samples, and the ease with which they can be prepared all contribute to the potential for microwave energy and microwave wastewater detection application.