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.
[1]
T. L. Wadley.
THE TELLUROMETER SYSTEM OF DISTANCE MEASUREMENT
,
1957
.
[2]
R. Harrington.
Time-Harmonic Electromagnetic Fields
,
1961
.
[3]
C. R. Grant,et al.
Back Scattering from Water and Land at Centimeter and Millimeter Wavelengths
,
1957,
Proceedings of the IRE.
[4]
A. Karbowiak.
Theory of imperfect waveguides: the effect of wall impedance
,
1955
.
[5]
Jacques Renau,et al.
Measurements of electromagnetic back-scattering from known, rough surfaces
,
1965
.
[6]
J. D. Dyson.
The Measurement of Phase at UHF and Microwave Frequencies
,
1966
.