BROADBAND ANNULAR DUAL-POLARIZATION RADIATION ELEMENT AND LINE SHAPE ANTENNA ARRAY

摘要

The invention discloses a bi-polarized braodband radiation unit of annular type and a linear array antenna incorporating the same. The radiation unit is used to be mounted to a metal reflection plate so as to form a communication antenna. The unit includes two pairs of symmetric dipoles for transmitting or receiving communication signals, one pair of symmetric dipoles being orthogonal to the other pair of dipoles in their polarity, said two pairs of symmetric dipoles defining together an annular structure; a plurality of baluns each corresponding to respetive symmetric dipole, said each balun serving to feeding current to respetive symmetric dipole in a balanced manner. Each symmetric dipole has two unit arms disposed symmetrically on respective balun, said two unit arms being symmetrical about said respective balun. One end of each unit arm is coupled to respective balun, while the other end thereof has a downwardly extended loading post formed thereon. Each unit arm has a plurality of tuning bars, and the cross-section area of each tuning bar is greater than that of the unit arm. The bi-polarized broadband radiation unit provided by the invention has a wide bandwidth, high efficiency, high isolation, high cross polarization discrimination, as well as low discreteness of beamwidth over changes of the frequency. Therefore, it can be used independently as a single antenna and more often, it can function as a base unit to form an array antenna.