Modelling the Dielectric Constant of Rice Grains

ABSTRACT. A new technique for the measurement of dielectric constant of materials, using a partially filled waveguide cell and a new mixture equation, has been developed which is first tested for teflon and then used to measure the dielectric constant of rice and air mixture in the frequency range of 2.6GHz to 3.9GHz. The values of dielectric constant of rice grain obtained using the mixture model varied between 4.5 and 7.0. The dielectric constant of rice grains generated by the new model compares well with the present experimental data and published data of You and Nelson. The moisture content of rice was also measured by slow drying of three different samples of rice in an oven which was found to be 11.6%. The packing fraction of rice grains in the waveguide cell is 0.641, which was further increased to 0.81 by using a mixture of rice grains (80% by weight) and rice powder (20% by weight).