Measurement of dielectric constant using a microwave microstrip ring resonator (MMRR) at 10 GHz irrespective of the type of overlay

A new equation to measure the dielectric constant of materials using a microwave microstrip ring resonator (MMRR) at 10 GHz by empirically modifying the design equation of the effective dielectric constant of the system is proposed. Each material, with the proper size of interest, is overlaid on the MMRR and the change in resonance frequency caused by the change of effective dielectric constant of the system is measured, which depends on the dielectric constant, thickness, and type of overlay (complete or partial). No equations are available for obtaining the dielectric constant of the materials, which are used as partial overlays. The proposed equation can be used for both a complete and a crossed partial overlay. Validation of the equation is done using different dielectric materials and is in good agreement with the experimental results (within±1%). This will be useful in applications such as grain-moisture sensing using/MMRR.