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 selfsimilar 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.