Tham khảo tài liệu 'electromagnetic waves propagation in complex matter part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Quasi-planar Chiral Materials for Microwave Frequencies 107 curing temperature. We observe that the rotation angle decreases when the frequency increases which means that the resonance frequency is below the measurement range. As it can be expected the rotation angle increases with the number density of inclusions and with the sample width following a nearly linear relation. Similar behavior has been found in other experiments with helices Brewitt-Taylor et al. 1999 or cranks Molina-Cuberos et al. 2005 . Rotation angle 14 15 16 17 18 Frequency GHz Fig. 11. Rotation of the polarization plane for a plane wave normally incident over a planar array of gammadions Fig. 10 and for different supporting boards free space magenta FR4 blue unlossy CER-10 green and lossy CER-10 red . The result is the same in front and back incidence. Planar distributions We have modeled using CST Studio SuiteTM 2009 the rotation of the polarization plane for a plane wave normally incident over a plane structure similar at a different scale to the one studied by Papakostas et al. 2003 . Our structure is also an array of gammadions Fig. 10 that in this case presents resonance in the microwave band. The rotation has been determined assuming different properties of the board that supports the array first assuming it has the same properties as vacuum second a typical material on PC Boards FR4 sr and finally a high permittivity material like Taconic CER-10 sr 10 all present in CST Studio SuiteTM 2009 library. The results are shown in Fig. 11. In the first case vacuum the structure is symmetrical in a normal axis so it is not chiral in 3D the specular 108 Electromagnetic Waves Propagation in Complex Matter image is coincident with the result of a rotation around a longitudinal axis so there is no electromagnetic activity no rotation . When taking into account the effect of the board the structure becomes 3D chiral. In this case we observe electromagnetic activity which .
