Microwave cavity perturbation technique for high-temperature dielectric measurements

Abstract

The present work is motivat microwaves for the catalytic conversion of c carbon monoxide. Chemical reactions like thi catalyst temperatures of more than 800 °C. design of the microwave assisted reactor re knowledge of the dielectric properties of the cat support materials up to those high temper purpose a measurements system based on the ca method was built. The system is using a rectang with a resonance frequency at 2.45 GHz and Q § 12000. A novel synthetic calibration m numerical full-wave modeling has been d alternative to traditional calibration methods. T temperature dielectric measurements for polye (PEEK), MACOR glass ceramics and zirconia a Index Terms -Cavity resonators, high temp measurements, numerical simulation, perturbat

Dielectric characterization of concrete at high temperatures

“…The heating and positioning of the sample as well as the data acquisition are fully automatized using a personal computer. A more detailed description of the apparatus can be found in [17]. In our experiments we used cylindrical concrete samples with about 8 mm in diameter and 10 mm in height (~0.5 cm 3 in volume).…”

System for in-situ dielectric and calorimetric measurements during microwave curing of resins

“…2 the calibration coefficients and from the equation (1) and (2) have to be determined. According to the study presented in [2] the coefficients A and B are not constant, but depend on the dielectric properties of the material under test. For this purpose a numerical calibration can be implemented with the help of a 3D full wave simulation.…”

“…For this purpose a numerical calibration can be implemented with the help of a 3D full wave simulation. It was realized with CST Microwave Studio for the range of the expected dielectric properties [2]. Thereafter the spline interpolated −1 ( − , 1 − 1 ) and In the equation 2 for the cavity perturbation theory, coupling effects are not accounted.…”

“…A variety of methods for measuring of dielectric parameters of materials over predefined heating scenarios have been developed during recent years [1][2]. Usually, the choice of the most appropriate measurements technique depends on such factors as the range of the expected dielectric properties, the operating frequency, the required measurement accuracy, the sample geometry, and, finally, the aggregate state of the material under test.…”

“…If this assumption is fulfilled then the parameters A and B depend on the cavity and sample geometry and the kind of resonant mode only. Under real conditions, however, where changes of the electric field are not negligible, A and B depend also on the dielectric properties of the sample [2].…”