Investigation of the Dielectric Properties of Grain at Microwave Frequencies

The components of the complex dielectric constant of feed grains are obtained for the 8.5 to 12 gHz frequency range. The short-circuited wave guide method is employed to provide null-shift data for computer calculation of the first-order approximation of the real part of the complex dielectric constant under the simplifying assumption of negligible loss. Correction to this value is then made, where appreciable, by calculating the loss tangent from attenuation data independently obtained for the grains. The imaginary part of the complex dielectric constant then is obtained by multiplying the loss tangent by the real part. Curves of the real and imaginary components are plotted versus frequency for two moisture levels each of corn, soybeans, wheat, and barley