A broadband reflectarray antenna with double square rings as the cell elements

A reflectarray antenna composed of double square rings of variable lengths that are etched on a conductor backed substrate is proposed for bandwidth enhancement. Using this technique, a single layer reflectarray that has a wider bandwidth compared to conventional single layer reflectarrays is designed, fabricated and tested. Measured results demonstrate radiation efficiency close to 52% and 1-dB gain bandwidth of 9%, centered at 22.0 GHz. Another class of "loop" cell element namely, double cross loop, is also used as the building block of reflectarray and simulation and measurement results that demonstrate a comparable performance in the order of what was achieved for the reflectarray composed of square rings, are presented.