Patent ID: 7242368

Claim:
A multibeam antenna comprising: a PBG material (Photonic Bandgap) suitable for the spatial and frequency-wise filtering of electromagnetic waves, this PBG material exhibiting at least one stopband and forming an exterior surface (38; 158) radiating in emission and/or in reception, at least one defect of periodicity of the PBG material in such a way as to create at least one narrow passband within said at least one stopband of this PBG material, and an excitation device suitable for emitting and/or receiving electromagnetic waves inside said at least one narrow passband created by said at least one defect, wherein: the excitation device is suitable for working simultaneously at least around a first and a second distinct working frequency; the excitation device comprises a first and a second distinct and mutually independent excitation element, each suitable for emitting and/or receiving electromagnetic waves, the first excitation element being suitable for working at the first working frequency and the second excitation element being suitable for working at the second working frequency; the or each defect of periodicity of the PBG material forms a leaky resonant cavity exhibiting a constant height in a direction orthogonal to said exterior radiating surface, and determined lateral dimensions parallel to said exterior radiating surface; the first and the second working frequencies are suitable for exciting the same resonant mode of a leaky resonant cavity, this resonant mode being established in an identical manner regardless of the lateral dimensions of the cavity, in such a way as to create on said exterior surface respectively a first and a second radiating spot, each of these radiating spots representing the origin of a beam of electromagnetic waves radiated in emission and/or in reception by the antenna, each of the radiating spots exhibits a geometrical center whose position is dependent on the position of the excitation element which gives rise thereto and whose surface area is greater than that of the radiating element giving rise thereto, and the first and the second excitation elements are placed one with respect to the other in such a way that the first and the second radiating spots are disposed on the exterior surface of the PBG material side by side and overlap partially.