Partially-open SIW resonator for microwave characterization of particulate dielectrics: Effect of interaction with gases

This work describes a novel measurement technique for determining the complex permittivity of powdered materials, based on resonant-perturbation of a Substrate Integrated Waveguide (SIW) resonator operating at ∼2.5 GHz and calculations from General Dielectric Mixture Model equations. The proposed method is validated with standard powder samples measurement and comparison with the measured data by 3D electromagnetic simulation. The influence of the powder density is also discussed. The technique is then used to investigate the effect of hydrogen gas adsorption and humidity on the dielectric properties of tin oxide and zinc oxide powders, respectively. The SIW-resonator is a low cost and simple structure with good sensitivity. It is adapted for dielectric characterizations of both semi-solid and non-solid materials.