Selection of Suitable Feeding Mechanism for Maximum Gain in Reflectarrays

Feeding is a very crucial part in performance analysis of reflectarray antenna. A suitable type, position and distance of the feed in reflectarray can be selected to attain a desirable result. In this paper, a center feed reflectarray of 332 square patch elements is selected to find its suitable feed with proper distance for maximum gain performance at 26 GHz. The analysis is performed with three different horn feeds of 10dB, 15dB and 20dB gain. Additionally, the feed distance (f) with respect to the reflectarray size (D) is varied from 0.4D to 1.3D. It is observed that, the each feed offers a maximum gain at a different distance, even though the reflectarray is initially designed at a feed distance of 1D. The 10dB, 15dB and 20dB feeds offer their respective maximum gains at a feed distance of 0.8D, 0.9D and 0.5D respectively. Simulated results have been verified with measurements where a maximum measured reflectarray gain of 27.3dB has been obtained with a 10dB horn feed at a distance of 0.8D.