A dielectric resonator method of measuring dielectric properties of low loss materials in the microwave region

Abstract

A technique for the measurement of dielectric properties of low loss and homogeneously isotropic media in the microwave region is studied. The measuring structure is a resonator made up of a cylindrical dielectric rod and conducting plates. The dielectric constants and loss tangents are computed from the resonant frequencies, structure dimensions and unloaded Qs of the TE 01δ mode. A simple field model is introduced to analyze this resonator structure. Unlike other simple models, this model does not have the defect of low measurement accuracy of dielectric properties. Important factors affecting the dielectric properties measurements are introduced. Error sources for measurements are also discussed. The measurement accuracy is justified by comparing the results with those of other techniques. In addition, various methods for calculating the power factor and conducting loss and for measuring the conductivity of the conducting plates are discussed. The accuracies of certain of these methods have not previously been studied, but are given in this paper. The swept frequency capability was also studied. It was found that dielectric properties in microwave frequencies could be measured within a frequency range of 3 GHz.

Theoretical Study of a High Permittivity Dielectric Resonator as a Potential NMR Probe

“…The field distribution is estimated by applying the approach developed by J. Sheen in [7]: the DR is shielded by two conducting plates placed far enough so that they do not influence the mode [4]. The computed magnetic and electromagnetic fields are displayed in Fig.…”

A parallel plate dielectric resonator as a wireless passive strain sensor

“…For a T E 01δ mode resonance, which is used in this work, the resonance condition is Equation 5. Itoh [26] and Sheen [6] proposed some further improvements, by replacing the perfect magnetic wall with a system of equations derived from an infinite rod waveguide, and by improving the estimate of the wave vector in the axial direction, respectively:…”

“…A modification of the Courtney method adds a gap between the plates and the resonators, this is done in order to decrease the power loss caused by induced currents in the conductor. This test setup, henceforth referred to the parallel plate dielectric resonator (PPDR), thus has a better resolution in measuring the dielectric loss tangent of very lowloss materials [6].…”

Comparing Saddle, Slotted-tube and Parallel-plate Coils for Magnetic Resonance Imaging

“…To design a modified RF probe resonator, numerical simulation in a wide-frequency band is often required. The parallel plate resonator has been well investigated in non-MR research areas [21], [22], and the magnetic field B 1 (r) between the parallel plates has been shown to be homogeneous [20], [24].…”