Abstract
The microwave property of materials is very important in industry and academic research. The property will vary with the applied wave frequency and magnitude. Characterizing the complex permeability of ferrite materials provides the essential information for the developments of many useful microwave devices, such as circulators, isolators, phase shifters, and high-speed switch. This study adapts the resonant methods where the samples are placed at the magnetic field maximum to strengthen the coupling. Two specially designed cavities are employed to determine the permittivity and permeability, respectively in 2.45GHz band. One is operating at cylindrical qusi-TM 010 mode with coaxial coupled structure, and the other is operating at a quasi-TEM mode with very high sensitivity of the permeability. We use the cavity characteristic and iteration method to improve the measured results. The pros and cons of these two resonators will be discussed. The experimental results of several classical magnetic materials will be shown.