The objectives of this research were to investigate the influence of various factors on radio frequency (RF)
power distribution in dry food materials, placed in a 12 kW, 27.12 MHz parallel plate RF system, using a
validated finite element computer model. The factors investigated were sample size, shape, relative
position between the RF electrodes, and dielectric properties (DPs) of the sample and the surrounding
medium. Effects of electrode gap and top electrode configuration on the RF power distribution behavior
of the sample were also studied. The RF power uniformity in the samples was compared using RF power
density uniformity index (PUI). Simulated results showed that the RF power uniformity in cuboid shaped
samples, placed on the bottom electrode, first decreased and then increased with the increase in sample
size. The sample shape and its vertical position between the fixed gap parallel plate electrodes also
affected the RF power distribution and uniformity. A cuboid sample had higher RF power densities at
the edges, while an ellipsoid had higher power densities in the center parts. Simulated results showed
that the smaller values of DPs resulted in better RF power uniformities in the samples. Reducing the
electrode gap improved the RF power uniformity of the sample. While studying the influence of the
top electrode configuration on the RF power distribution and uniformity, the results showed that optimum
RF power uniformity in a particular sample size could be achieved with a particular top electrode bending
position and angle. The results are useful in understanding complex RF heating, designing and scaling up
of efficient RF systems.