Array Reflector Antenna

With the rapid social development, the traditional reflector is out of date due to its ponderous and bulky shortcomings in modern communication. Because of this, the design about a new kind of reflectors called reflectarray was initiated. This kind of reflectors possessed the advantages of the traditional reflectors and the phased arrays. The reflectarray is made up of lots of resonant elements. When the feed radiate the reflectarray, the reflected wave could be focused at some desired direction owing to the adjustment of each element.In this paper, first of all, the review about the development of reflectarray in the last decade is presented, including some representative reflectarray structures. The reflectarray is primarily consist of two classes: the one that could directly adjust the resonant frequency of the reflectarray element and the one that could adjust indirectly. In addition, through the study about the different kinds of reflectarray, two kinds of reflectarray element are being introduced. Utilizing the benefits of varactor and bowtie and fractal structures, some interesting characteristics of these elements were found.Furthermore, some basic knowledge about the system design and analysis about the reflectarray is also presented. Based on the dual slot theory, the method that could compute the basic performance of the reflectarray is introduced, including the relationships between some primary reflectarray design parameters and the working efficiency as well as the working bandwidth of the reflectarray.In the design of reflectarray, the couplings between each element could usually bring lots of influence to the overall performance of the reflectarray. In this paper, first of all, we studied some basic coupling knowledge of the reflectarray, and after the study about the PBG, a kind of method that could reduce the mutual couplings of each element is presented, and brings some benefits for the design of the much more compact reflectarray.