High-Gain Omnidirectional Horizontally Polarized Dipole Array for Sub-6 Base Station

Abstract

A novel omnidirectional horizontally polarized (OHP) dipole antenna array with wide bandwidth and high gain is reported, which operates at Sub-6 band. A major improvement is the feeding method for omnidirectional radiation patterns which is inspired by classic turnstile antenna array. Six pairs of modified cross dipoles are positioned along a parallel feeding wire transmission line, and the dipole elements are placed in two orthogonal planes, with six dipole elements in each plane. The adjacent dipole elements on different planes are spaced by a quarter wavelength to produce an omnidirectional radiation pattern. The antenna array is simply machined with 1 mm diameter copper wire and fed by a coaxial structure at the center of the array. The max cross-section area is 3.17×0.5 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> which can be limited in a cylinder. The measured and simulated results are in good agreement. The measured -10 dB impedance bandwidth covers 1.19 GHz from 3.83 to 5.02 GHz and the measured peak realized gain (RG) value is 7.44 dBi. The measured 1dB gain bandwidth of the proposed antenna is 1 GHz (22%) from 4 to 5 GHz. The advantages of high gain, broadband, omnidirectional radiation, and low cost make this antenna favorable in base station situations.