Study of non‐linear variation of dielectric constant with moisture for mug grains using microstrip ring structure

The non‐linear variation of dielectric constant with moisture in the grains using a microstrip ring resonator (MRR) is reported. A MRR is perturbed using mug grains ( Phaseolus Radiatus Linn.) having different moisture contents (7% to 42%), at 8 azimuthal orientations (partial overlay). Out of the two orthogonal degenerate modes (even and odd) of the MRR, only the even mode is sensitive to the strength of perturbation (grain moisture). The perturbation equation for even mode resonance frequency f e reported by Yogi et al. [5] is modified for the present case. It is seen that the variation of dielectric constant with moisture content in the grains is non‐linear.