Design and Implementation of a Cylindrical Microwave Sensor to Measure the Water Content of Brake Fluid

The braking device depends on brake fluid to move pedal force to its braking components. Brake fluid containing excessive water levels diminishes braking performance while generating additional danger to brake system elements. Research has developed a cylindrical microwave sensor which performs real-time non-invasive water content detection in brake fluid while presenting a cost-effective and modern approach to phase separation monitoring. Experimental tests run at the Ministry of Science and Technology’s Industrial Research and Development Department confirmed the cylindrical cavity's operating capability. The sensor uses a brass cavity made of 67% copper and 33% zinc with a horizontal flow system and passes through an acrylic tube 4 cm in diameter. The sensor operates between 3 and 4 GHz microwave frequencies to monitor S22(Sparameters) reflection data for detecting multiple levels of water content in brake fluid solutions between 30% and 70%. The experimental data showed specific frequency shifts occurred when water content changed because elevated water amounts produced rises in peak frequency and energy level intensification. Experimental outcomes verified through HFFS simulation showed a testing range from 92% to 80%. The results indicated that water con-centration increases both shifts the frequency pattern and enhances energy capture and modifies dielectric properties while peak frequency amplitude responses proportionally to the water con-tent levels. The study examines how the sensor works to enhance brake fluid performance through valid links between pure water measurement and changes in fluid electrical properties as well as temperature-dependent changes in fluid viscosity. Vehicle durability improves through this technology which simultaneously produces cost-effective maintenance and paves the way for comprehensive industrial fluid-quality assessment capabilities.