Design of Single-Feed Multi-Beam Reflectarray Using Iterative Fourier Techniques

Abstract

Reflectarray antenna with multiple simultaneous beams is a promising antenna candidate for the multiple beam applications. A comprehensive and systematic study on the design of single-feed multi-beam reflectarray antenna is presented in this paper. The traditional direct design method, called aperture field superposition method, is investigated first. It is demonstrated that although this method can generate a multi-beam pattern, it cannot provide satisfactory performances, mainly because of high side lobe level, gain loss and beam deviation. The iterative Fourier technique is then applied to optimize the performances of the multi-beam reflectarray antenna. The required mask and cost function for multi-beam design and the flow of the iterative Fourier techniques are represented. Finally, a Ku-band four beam reflectarray with a single feed is designed using the iterative Fourier techniques and the radiation performances are analyzed and compared with that of single beam, as reference case, and multiple beam designed by aperture field superposition. The numerical results show that a good four beam performance can be obtained by using the iterative Fourier techniques, which suggests that the iterative Fourier technique is suitable for the design of the multi-beam reflectarray antenna with a single-feed.