Microwave Surface Level Monitor

Nonconventional applications of a microwave multifrequency CW radar for contactless and continuous monitoring of liquid surface levels are discussed. Analytical and experimental analysis utilizing the multiple-frequency technique to eliminate ambiguous distance measurements are presented. The method makes use of a waveguide partially immersed in the liquid and allows the measurement of phase differences between the outgoing and reflected waves, which is then utilized to determine the liquid level. Potential applications of the proposed method are the monitoring of water levels in piezometers and other liquids in large storage tanks.