Evanescent microwave probe study on dielectric properties of materials

A recently developed evanescent microwave probe (EMP) technique combined with systematically quantitative analyses is demonstrated. We use a three-dimensional (3D) finite element simulation to model the electromagnetic field inside the resonant cavity and inside the sample near the tip. We also proposed an analysis model for the sample's quality factor (Q), which is usually hindered by the conductor losses of the resonator. Measurement on various dielectric samples agrees very well with the theoretical model, demonstrating the validity of analyses for the EMP resonator and providing a possibility for dielectric imaging the surface of the samples with high resolution.