  The electromagnetic metamaterials at microwaves frequencies are well
established in industrial applications nowadays. Recent research has shown that
a specific kind of metallic metamaterial can contribute to improve the
performance of the microwave feedhorns used in radioastronomy and satellite
telecommunications. In this article, we theoretically justify this argument
finding a new type of meta-ring with a record bandwidth in terms of
cross-polarization, and we explore the manufacturability of these particular
metamaterials, successfully fabricating a meta-ring and applying it to a novel
and very compact prototype microwave antenna which covers a 2:1 bandwidth.
