Characterizing the Complex Permittivity and Permeability with a Dual Cavity System
Tsai, Cheng-Hung1*, Wong, Wei-Syuan1, Chen, Yen-Ren1, Chao, Hsien-Wen1, Chang, Tsun-Hsu1
1Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Tsai, Cheng-Hung
Characterizing the electromagnetic properties of materials helps us to understand how the wave interacts with materials. The resonant cavity perturbation technique is commonly used. Unfortunately, the perturbation method suffers from the intense interplay between electric and magnetic fields and is unable to characterize precisely the permeability because of the influence of the permittivity. Here we propose the dual-cavity system, which can almost separate the coupling of the electric and magnetic fields and allows us to characterize the complex permittivity and permeability, independently. We prepared samples including three homemade epoxy-based composites (Fe3O4, silver, and carbonyl iron) and a commercial ferrite. The complex permittivity and permeability of each composite can be determined and be well analyzed with the effective medium theories. With external magnetic fields, the electromagnetic properties of each composite change differently due to their intrinsic magnetism. For the ferrite garnet, distinct transverse electromagnetic (TEM) modes are enhanced with different magnetic bias fields.

Keywords: Field-enhancement method, Resonant cavity, Material characterization, Metamaterials