Numerical Methods In LHM Design And Medical Images

Numerical method is a method of researching and solving approximate math problems’solutions. It is used in the computer to solve math problems, referred to the calculation method. Numerical method has been used in various fields of scientific research and industry. In this paper a new kind of left-handed material cell structure was designed out under the help of FDTD method. Left-handed Material’s electromagnetic properties exhibit negative permittivity and permeability. Because LHM has some other unique electromagnetic properties, it has become a hot topic in many fields such as materials science, electromagnetic, biomedicine. Based on the previous experience and finite difference method, a new kind of LHM cell structure was designed out. The structure is etched on one side with small size. It has excellent performance and is used in the antenna field. On the othe hand, the finite element analysis has been used in the biomedical engineering. Three-dimensional finite element models of teeth were established and they provide a reliable clinical data for stomatology.The main work and creative points of the thesis can be summarized a s bellows:1) Basic concepts and principles of numerical calculations were introduced. And several commonly used numerical methods were introduced.2) Properties of LHM were discussed in detail. Its research progress in recent years was summarized.3) With the help of FDTD softwared, a new kind of LHM cell structure was designed. It consists of semi-cirtular symmetry and short metal rod and shows left hand properties in X-band. Its electromagnetic properties were discussed. By the computational electromagnetics simulation tool this structure was proved to have backward wave property.4) This LHM structure was used in the design of the antenna array. Combined with the new structure, the2.6GHz antenna array improves its radiation characteristics, reduces the electromagnetic coupling between adjacent antenna elements. Computer simulation and optimization were made then.5) The finite element analysis is applied to the field of biomedical engineering. A tooth modeling design was achieved by FEM simulation analysis. With the image processing software Mimics, the model’s cross-section and longitudinal section were analysed. With the FEM software Ansys, a number of tooth models were established. By comparing the preoperative and postoperative tooth FEM model, the cleaning effect of decayed tooth and tooth loss were analysed. Furthermore, the effect by handpiece bur was provided.