Berthold BTwave LB 571-02, Operating Manual

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3 System Description LB 571 BTwave
10
68847BA2 Rev.00, 10/2020
3.2 Measuring Principle
Microwaves penetrate the bulk material, causing a rotation of the free water mol-
ecules. Placing a moist material on the field of the sensors causes a decrease of the
resonance frequency and quality factor of the resonator. Both effects are measured
and used as a direct indication of the moisture content.
The resonator consists of a ceramic disc, which is embedded in a metal plate. The
upper side of the ceramic remains without a metal layer. From this side, the elec-
tromagnetic field interacts with the product to be measured. The measured data
are processed in the integrated evaluation unit and output as a measurement sig-
nal.
Figure 2 Measuring Principle