Circularly polarized antenna has often been used in mobile communication. For narrow bandwidth requirement, microstrip patch antenna can be employed. For wide bandwidth operation, slot-ring antenna may be more suitable. Slot ring antenna also has more axial ratio bandwidth than the patch. This patent relates to a new broadband circularly polarized slot ring-type antenna. Two square slot rings are linked over the corner and are printed on ground plane of an FR4 substrate to achieve circular polarization from 2.65GHz to 3.7GHz. The structure can also be viewed as a combination of two perturbed square rings. The perturbation is achieved by adding an inward L-shaped slot protrusion from each ring.

利用雙鍊結環產生約40%頻寬之圓極化天線

提供產生30%頻寬之圓極化天線