Main Claim

A broadband antenna comprising a reflector-constituting plane and, in the vicinity of said reflector-constituting plane, at least one transmit/receive radiating element,said antenna further comprising, disposed substantially in superposition on said reflector-constituting plane and said transmit/receive radiating element, an assembly of defective EBG (Electromagnetic BandGap) material elements, each substantially plane defective EBG material element being parallel to said reflector-constituting plane, and at least one of the characteristics of magnetic permeability, of dielectric permittivity, and/or thickness in the direction perpendicular to said reflector-constituting plane being substantially different from one defective EBG material element to another, the assembly formed by said reflector-constituting plane and said assembly of defective EBG material elements forming a leaky resonant cavity.