A spatial beam splitter design using fishnet-based metamaterial

• Main Authors: Hsu, Neng-Chieh, 許能傑
• Other Authors: Hwang, Ruey-Bing
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/91628808016176802111

碩士 === 國立交通大學 === 電信工程系所 === 97 === In this thesis, we presented a 4-way spatial beam splitter consisting of two-dimsnsional fishnet-based periodic structure. By properly designing the periods and aperture size of the fishnet, the periodic medium can possess a effective refractive index close to zero. Furthermore, from Snell’s law we know that the refractive wave outgoing from a medium with refractive index near zero will tend to be perpendicular to its interface connecting to a medium with refractive index greater than unity. Based on this principle, we put a line source in the metamaterial to excite the four beams normally radiating from the four sides of the rectangle-shaped metamaterial. To enhance the radiation directivity, each of the openning is equipped with a E-plane horn type structure. The major contribution of this theses contains twofolds: (1) the dispersion and phase relations of the two-dimensionally periodic structure was systematically calculated to explain the extraordinary propagating characteristics of waves in the metamaterial with near-zero effective refractive index, and (2) in addition to the theoretical calculation, the experimental measurements were carried out to verfy the theoretical studies. Last but not the lease, a good agreement between the theoretical and experimental results was obtained.