Research On Fabrication And Performance Measurement Of The Helix Structure Chiral Materials

Chiral material is a new type of electromagnetic functional materials. It was compounded by mixing random orientation chiral inclusions equably to a certain matrix material. Compared with normal electromagnetic material, one important character of chiral material is that it can arouse cross polarization between electric field and magneticfield, and it has extra electromagnetic parameter adjustable-chirality parameter.Owing to some of its novel characters, chiral material had good prospect of applications in wide range of fields, such as wave absorbing materials, antenna project, microwave and millimeterwave devices etc. Surrounding the structure and electromagnetic performance measurement of chiral material, the thesis had researched deep and systematical in both theory and experimental aspects.In the theory aspect, the thesis gives deductions about wave equation, the characteristic wave vector, the characteristic wave impedance of electromagnetic wave in the chiral material, and that of reflecting propagation coefficient with/without metal-backing, according to Maxwell equations system and the constitutive relations of chiral medium. The dominant mode of electromagnetic wave in chiral circular waveguide is analyzed, the measurement principle of circular waveguide method is given, the mechanism of rotation and absorbing of the chiral material were analyzed. On the experiment aspect, chiral samples were made, using copper helix and carbon fibre helix as inclusions respectively, and then paraffin, PAN, the composite of PAN and MnZn, the composite of PANand Fe₃O₄ as matrix respectively, With self-made circular waveguide measurement system, the electromagnetic parameters of each sample were measured in 8.5-11.5GHz frequency rang. Finally, and the paper made fur study on how helix constitutive parameters, helix concentration and matrix affected electromagnetic parameters of chiral material. The experimental results showed that the outcome of circular waveguide method is consistent with the that of free-space method, circular waveguide measurement system is economical and practical value. The electromagnetic...