Design Of Antenna Based On Transformation Optic

Based on the invariance of Maxwell’s equations under the coordinate transformation, the theory of transformation optics (TO) provides a new way of manipulating the electromagnetic waves and becomes one of hot topics in the electromagnetic field of recent years. The method enables the control of the electromagnetic wave within a particular area by designing the distributions of material parameters via coordinate transformation. However, the material parameters derived from the transformation medium are often anisotropic and 3D variant, which is hardly to find the fitting materials in nature. Fortunately, with the significant developments of metamaterials in the past decade, it opens a possibility of implement the resulted material into reality. Therefore, the robust combination of TO and metamaterial has largely promoted the development of electromagnetic design. Our work is thereby motivated and main work and innovation points are as following:1. According to the theory of inverse transformation optics, the paper proposed a design of transition lens, enabling the arbitrary redirection of radiation waves. Here, the detailed analyses to its theoretical derivation are presented. Meanwhile, the influences of structural parameters is further discussed. It suggested that special care should be given on the thickness of the lens. Furthermore, comparative studies have been carried on phase manipulation and amplitude manipulation. Finally, we realize an adjustable surface radiation direction.2. As an extended study of the above, we propose a design of a meta-surface, successfully realizing the conversion from propagating wave into surface wave. Deep analyses have been given to investigate the influence of the structural parameters on its performance. Similarly by quasi-conformal mapping and the process of discretizing, approximation and drilling, a pure dielectric convertor can be implemented, thus providing a possible design for microwave harvesting.3. Based on the design of converting the propagating wave to surface wave, carefully choosing a proper coordinate transformation can lead the leakage of wave towards the predefined direction, thus realizing a simple form of leaky-wave antenna. The research in this section provides a new way of designing the leaky wave and holographic antennas.From the above studies, inverse transformation optics has more flexibility and effectiveness in the manipulation of electromagnetic waves, it has more physical sense and thus is more suitable for the design of the antenna application, providing useful guidance for future application of theoretical analysis and practical engineering.