Design of circularly polarised beam-shaped RAs using a single layer of concentric dual split loops

作者:Yu, Jianfeng*; Wang, Junhui; Chen, Lei; Yang, Jing; Shi, Xiaowei
来源:IET Microwaves Antennas & Propagation, 2016, 10(14): 1515-1521.
DOI:10.1049/iet-map.2015.0701

摘要

This study presents the design of circularly polarised beam-shaped reflectarrays (RAs) based on a rotational element. This element is a single layer of concentric dual split-loop structure using multi-resonance technique to improve the unit bandwidth. For accuracy and efficiency, a new multi-step convergence strategy has been used in the intersection approach to avoid local minima. This strategy leads the optimisation to the solution independently of the starting point by gradually varying the target pattern. Two kinds of shaped beams have been calculated. A medium-sized RA has been designed for a local multipoint distribution system application to validate the modified approach. The numerical result suggests good convergence without critical starting point demand for the intersection approach. The other RA is designed, manufactured and tested for quad-beam radiation, and it presents a 12.1% 1 dB bandwidth from 13.1 to 14.8 GHz with the axial ratio <3 dB. All the results suggest the rotational element can be a good solution in beam-shaped RA designs.