| Summary: | 碩士 === 國立交通大學 === 電信工程研究所 === 105 === In this thesis, we proposed the use of metasurfaces to design and synthesize the double-focus generalized Luneburg lens (DF-GLL) at microwave frequencies. The unit cell of the metasurface used for the synthesis of the lens is made of a square metallic patch printed on a grounded dielectric substrate. Then, we observe that the dispersion of square unit cell varies with the different incident angles, that is, this square unit cell is directionally anisotropic. However, the surface waves will bend at all locations on the lens. The use of only one surface wave propagation direction in synthesizing the refractive indices of all locations on the lens may thus be inaccurate. Thus, we propose a method to improve the synthesis of the DF-GLL. The improvement method is that tailoring the direction adapts to the orientation of the ray path direction at any position within the lens relative to square patches that represented the required refractive index at the same position. We believe the method is more accurate to synthesize the lens, and can improve the performance.
Finally, with this proposed synthesis method, we have demonstrated that DF-GLL metasurfaces are able to successfully achieve two clear focal spots by simulation and experimental results.
|
|---|
