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

Abstract

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.

TEMPO-oxidized cellulose nanofibre (TOCN) films and composites with PVOH as sensitive dielectrics for microwave humidity sensing

“…To validate their dielectric sensitivity to humidity in test conditions, the dielectric constant of TOCN gels was tested under variable humidity conditions using the characterization method presented in [31].…”

“…The resonant frequency for each humidity level was measured and compared to the resonant frequency without TOCN. From the measured frequency shift, EM analyses were performed, and a calculation algorithm implementing the characterization method in [31] was applied to rigorously extract the values of the dielectric constant for each humidity level.…”

Nondestructive Evaluation of Fluid Characteristics using Compact Quarter-Mode SIW Resonator Sensor

“…[10,11]. Several sensors are implemented using various techniques, including SIW [10][11][12][13][14][15][16][17]. However, these sensors are available in larger sizes due to the use of full-mode SIW technology.…”

Substrate integrated circular cavity resonator filled with nano-fibrillated cellulose for humidity detection

“…Recently published articles have also demonstrated that SIW can be used for sensing applications. For example, SIW resonators have been used to detect or characterize a fluid in a system or to characterize materials [13]. To the best knowledge of the authors, no investigation of fully biodegradable materials for humidity sensing in passive microwave devices has been reported.…”