A Beam-Scanning Printed Dipole Antenna Fed by a Rectangular Patch With Periodic Structures

In this letter, a beam-scanning printed dipole antenna fed by a rectangular patch with periodic structures is proposed. A simple rectangular patch embedded with rampart line structures is used as the novel feeding structure for the planar dipole. The embedded rampart line structures are used to reduce the size and radiation of the rectangular patch, which facilitates feeding. By exciting the coupled modes of the dipoles, continuous and gradual phase differences for the dipole arms can be achieved so as to achieve beam scanning. A double-layer reflector and director are used to enhanced the antenna gains. In the simulated results, the dipoles radiated a beam that scanned from −48° to 14° in the azimuth planes as frequency changed. The measured results show consistent scanning beams within the operating bands from 3.16 to 3.24 GHz. The measured gain ranged from 3.27 to 5.58 dBi within the corresponding bands. Furthermore, the proposed antenna had a high radiation efficiency close to 90%, as well as a compact size.