Flanged coaxial microwave probes for measuring thin moisture layers.
We obtain an analytical, closed-form expression for the input admittance of a flanged, open-ended coaxial line radiating into a layered lossy material. The effect of higher modes as well as the dominant mode have been taken into consideration. The results obtained in the experimental measurement of the microwave reflection coefficient of the probe radiating into very thin water layers are described and compared with the results obtained from numerical calculations based on a theoretical model. The measurements were made in the 5.0-7.0 GHz range. The results demonstrate, for example, the usefulness of this type of device in measuring thin moisture layers in the outer layer of the human skin.
Body Water↗