An iterative design procedure for multiband single-layer reflectarrays: Design and experimental validation

A novel iterative procedure for designing multiband single-layer reflectarrays is presented. The multiband frequency behavior is achieved by simultaneously providing the desired phases at each operating frequency. A suitable reflectarray element shape formed by several concentric loops loaded with double stubs has been selected for achieving multiband operation. The problem of mutual coupling among the different self-similar resonating elements laying on the same substrate is analyzed and mitigated by employing an innovative iterative design approach. The proposed design approach is demonstrated by designing a tri-band single-layer reflectarray with widely spaced frequencies operating at 3.9 GHz (C-band), 7.5 GHz (X-band), and 12.5 GHz (Ku-band). The single-layer prototype is compact and lightweight as it has been fabricated on a thin Kapton film glued on to a Rohacell HF31 substrate. The overall thickness is approximately λ 0/5 at the highest operative frequency. Measurements of the reflectarray radiation patterns agree with the estimated performance and prove the reliability of the proposed synthesis technique.