A Novel Broadband Dual-Polarization Antenna Utilizing Strong Mutual Coupling

A novel broadband dual-polarization antenna utilizing strong mutual coupling with high isolation is presented in this communication. The antenna is composed of two orthogonally situated dipoles which have square-loop shape arms (SLSAs). And to shape the radiation pattern of the antenna, a metal reflector is placed under the antenna. By elaborately utilizing the strong mutual coupling between the two dipoles, very good impedance match and sufficiently high isolation can be achieved simultaneously, the reasons for which are analyzed in this communication. Both the simulated and the measured results show that a more than 57.5% impedance bandwidth with SWR<;1.5 and port-to-port isolation>31 dB can be achieved for the proposed antenna. As an important advantage, the input impedance of the antenna can be controlled within certain limits by adjusting the configurations, thus the antenna can be fed directly by coaxial cables without using impedance transformers. Besides, the antenna structure is compact and simple.