A. Model of Capacitive Water Content Sensor
The following Fig. 1 shows a physical model of the
uniplanar scattering-field capacitive water content sensor.
Considering the interaction between drive plate and sense
plate, we assume that the length of plate (L) is infinite
and the edge effect is ignored. Calculating the uniplanar
scattering-field capacitance with unit integral method [28],
we can see from Fig. 1 that the increasing of the
tiny area (F = Lx) of capacitor can be expressed by