As any linear antennas can be considered to be comprised of a large number of dipole antenna, therefore the study of dipole antenna characteristics has a very important significance to the application of the general linear antennas. In this paper, Firstly, the radiation field of the dipole antenna is analyzed, and then the radiation field mathematic model of a specific structural antenna is established. The antenna is composed of two orthogonal half-wavelength dipoles, and the current phase of one dipole is advanced the other by 90°. According to the polarization theory of electromagnetic wave, the polarization of this antenna is discussed. The antenna pattern mathematical formula is deduced in horizontal and perpendicular plane, and the antenna pattern is given in graphics. Finally, a new method is introduced that the directivity of horizontal polarization component can be enhanced by increasing the number of antenna elements in the vertical plane, the simulation result show that this method not only enhance the energy of horizontal direction, but also restrain the radiation of other direction.