A study of microwave moisture measurement in bulk materials.
Moisture measurements play an important role in many material preparations and
industrial processes. Microwave techniques have been used for several decades
for such measurements. Shortcomings associated with the method have been
addressed. Graphical solutions used hitherto to obtain the permittivity from
waveguide measurements have been replaced by computer programs. The
accuracy of measurement have been improved by the development of waveguide
standards and the implementation of calibration procedures.
Permittivity measurements in through and short circuited rectangular waveguides
are reported on a wide range of solid, granular and liquid materials important to the
Techniques to suppress standing wave effects have enabled accurate plane wave
measurements of permittivity.
For bulk materials, new measurement probes have been developed for on line
measurements and associated with these probes lower cost instrumentation has
The· main outcome of the study is the improvement in permittivity measurements of
sample quantities of material. Moisture measurements in bulk materials have been
facilitated by novel non invasive probes.