Patent ID: 7589676

Claim:
An aperture-coupled antenna comprising: a first radiation electrode the geometrical shape of which is implemented to allow radiation of a circularly polarized electromagnetic wave; a ground area; and a wave guide which is implemented to supply energy to the antenna, wherein the wave guide is arranged spaced apart from the ground area on a first side of the ground area, and wherein the first radiation electrode is arranged spaced apart from the ground area on a second side of the ground area; wherein the ground area comprises an aperture including a first slot in the ground area, a second slot in the ground area and a third slot in the ground area, wherein the first slot and the second slot together form a slot in the shape of a cross, wherein the third slot passes through an intersection of the first slot and the second slot; wherein additionally the wave guide and the first radiation electrode are arranged such that energy can be coupled from the wave guide through the aperture to the first radiation electrode; wherein the third slot is implemented such that an operating frequency for which the aperture-coupled antenna is designed deviates by at most 30% from a resonant frequency of the third slot; and wherein the length of the first slot and the length of the second slot differ from the length of the third slot to allow the third slot at the operating frequency to be operated nearer to its resonance than the first slot and the second slot; wherein end portions of the first slot are spatially separated from the second slot and from the third slot; wherein end portions of the second slot are spatially separated from the first slot and from the third slot; and wherein end portions of the third slot are spatially separated from the first slot and from the second slot.