Phasing Characteristics of a Single Layer Microstrip Reflectarray Employing Various Basic Element Shapes

The reflectarray is the type of antenna that includes a feed similar to that used in a conventional curved reflector antenna but its reflector is planar and formed by an array of reflecting elements. These elements use a suitable phasing mechanism to beam an incident wave, as launched by the feed, in a desired direction. Recent years have seen a considerable interest in microstrip reflectarrays. One important issue in the design of microstrip reflectarrays is obtaining a wide phasing range and a slow phase variation (slope) as a function of the phasing element´s variable size. The present paper reports on investigations into the phase change with respect to the element´s size change (dPhi/dS) for a single layer microstrip reflectarray. The investigations are commenced with comparing phase response parameters (range, slope, and working size) for various element shapes that are adopted in a typical single layer microstrip reflectarray. Next, the effect of the substrate characteristics such as its dielectric constant and thickness is considered. The study is carried out by applying full EM simulations of a single unit cell containing a phasing element.