EM Analysis Of Optical Scattering By Wings Of Morpho Rhetenor Butterflies With FDTD Method

The thesis emphasize on electromagnetic (EM) analysis of the optical scattering by wings of tropical butterfly called Morpho rhetenor with finite difference time domain (FDTD) method. The reason why wings of the butterfly look blue is analyzed in this thesis, and furthermore, this characteristic can be used for special commercial or military products design. The thesis includes the following works:1. Extensional plane technique is applied in the thesis, as a result, the traditional computational region selection method and corresponding incidence wave adding approach is modified, so that FDTD can be employed to analyze the EM scattering of the whole electrically large wings of butterfly in a smaller calculation region conveniently.2. Fourier transforming method is used only at several concerned frequencies, then near field to far field transformation is applied within these frequencies, consequently, calculation complexity and memory consuming is reduced rapidly with FDTD analysis for several frequency points and all angles.3. Aiming at the application to stolen technique or other material structural designing, not only the total reflection of intensity of light is analyzed, but also the radar cross section (RCS) is computed, thereby, the research can benefit to the future work.4. Based on the research above, parameters of the structural model in the millimeter wave band are designed, and then the associate model is analyzed with FDTD. The numerical results presented validate the feasibility of extending the bluffer wing model to millimeter wave band, so some initial works are done with the goal of absorbing material designation in the millimeter wave band for our country.The configuration of wings of butterfly have two characteristics as follows: 1) it only reflect blue light and other lights can pass though the wings of butterfly, 2) the scattering filed in back direction is very weak, it is strengthened in other directions 30 degrees to 60 degrees away from the back. These two characteristics mentioned above are what we want in modern stolen techniques, it provides a new approach for the absorbing material designation.