Analysis of Water Pollution by a Microwave Cavity Sensor

A portable microwave measurement system is presented as a potential tool for the detection of water pollutants. The sensing unit is a rectangular cavity designed to resonate in the fundamental TE101 mode at 1.91 GHz. The proposed system is tailored for the on-field deployment and constitutes a solution of lower cost compared to the usual ones based on a network analyzer. Experimental tests on water samples contaminated with chlorides and nitrates are carried out in controlled conditions. These confirm that the sensor is effectively capable to detect pollutant concentrations in excess of 10 mg/L, and thus below limit values fixed by current regulations.