Phase compensation for space-fed planar microstrip reflect-array

REFLECT-ARRAY is commonly referred to as an array whose reflector is a plane. Similar to parabolic antenna, the reflect-array is typically fed by a horn. Based on the far-field (FF) model, i.e., spherical wave model, the feed horn is assumed to have a fixed phase center so that designers can employ it as the phase reference to estimate the phase of the feed wave incident on the reflect elements and compensate for reflect-array. However, in some configurations, the reflect-array is fed in the Fresnel zone. In such cases, the FF model becomes inappropriate. The paper presents a new method to calculate the compensation phase for reflect-elements. This method utilizes the phase of the incoming wave on the reflector units as the reference to calculate the compensation phase. An array that is feed by a close horn is designed with the proposed method. The numerical results in comparison with the conventional phase center method show that the proposed method performs better.