A Novel Approach for Wireless Liquid Level Measurement Using SAW Sensor

In this paper, a capacitive sensor integrated with the Surface Acoustic Wave (SAW) sensor is used for liquid level measurement of a storage tank. The capacitive sensor is kept at the bottom of the tank, and the terminals of the capacitor are connected to the SAW sensor. The SAW sensor observes the change in capacitance. The variation in the liquid level of the tank is proportional to the phase shift in the interrogation unit. The proposed system is a hybrid type system which is capable of transmitting the measured information in the wireless domain, and the system does not require any onboard power-supply.