II. SENSOR DESIGN
The senor based on measuring technique of capacitance to
determine cultivated media moisture, relies on the high relative
permittivity of water (∼80) relative to solid matrix (∼3 to 8)
and air (∼1). Therefore, a change in water content of
a cultivated media can result in a significant change in
relative permittivity of the media. By developing an analytical
relationship between the change of the water content and
the associated change of relative permittivity, the volumetric
water content of cultivated media can be indirectly
estimated.