Capacitive level sensor for layered fillings in tanks and vessles based on metamaterial transmission line

The paper describes a concept for capacitive level monitoring of layered fillings in tanks and vessels. The sensor element consists of several capacitive measurement cells that are serially connected forming a so called left-handed transmission line. The read-out of this capacitor array is realized at high frequencies via only one terminal. The usage of a high operation frequency bears the advantage that the inherent frequency dependent reduction of the dielectric constant for a large number of materials (e.g. water) can reduce the dielectric contrast between layered fillings e.g. water and oil. This bears the potential of improved extraction accuracy. Additionally the cellular sensor structure allows the extraction of dielectric properties of the materials under test (MUT) and a plausibility check of the extracted filling levels.