Microwave sensor designs for viscosity measurements

Viscosity is related to the internal friction of a liquid and is defined as its resistance to flow. In particular, the viscosity values of fluids such as paint and thinner play an important role in application quality, surface coating performance and production processes. Traditional viscosity measurement methods are generally mechanically based and have some limitations in terms of sensitivity and ease of application. Therefore, new generation sensor technologies based on dielectric properties attract attention as an alternative approach to viscosity measurement. In this thesis study, the dielectric properties of different paint-thinner mixtures were examined in the 1-20 GHz frequency range and the relationship between viscosity and dielectric properties was revealed. Viscosity measurements; The flow rates of liquids were determined using the FORD4 plastic viscosity measuring cup and using the ElcoMeter application. For dielectric measurements, the dielectric probe method was used, which provides high-precision data collection. In line with the obtained dielectric data, two different sensor designs, based on microstrip antenna and transmission line, sensitive to viscosity changes, were developed. Sensor designs were made and analyzed using the finite integration based simulation program. Simulation results revealed that the proposed sensor designs offer a suitable method for analyzing the dielectric properties of paint and thinner-based liquids. The developed sensors can be considered as a potential alternative, especially for non-contact and rapid viscosity measurement.