A Design Method to Acquire High Gain for Omni-Direction Radiation Applied in WiMAX

This paper proposed a novel design method to acquire high gain for coaxial collinear sleeve dipole array antenna. Based on the analysis of S₂₁ of one element and two elements of the antenna, the current magnitude and phase on each element distribute equally. Thus high gain and good omnidirectional performance on the horizontal plane is obtained with the equilibrium of the energy on each element. Details of the proposed antenna design are described, and experimental results for the VSWR and gain are presented. The measured VSWR <2, bandwidth is to 11.5%. The un-roundness is about plusmn0.3 dB on horizontal plane and the least gain is 6.4 dB from 3.4 to 3.6 GHz, covering the WiMAX band.