Dual-Polarized Dipole Array with Controlled Beam Tilt and Wide Radiation Pattern for Multi-Beam Antenna of Base Stations

Abstract

A novel design of a dual-polarized dipole linear antenna array with controlled beam tilt in vertical plane and 90° beamwidth in horizontal plane is proposed for multi-beam antennas of base stations operating within the frequency band 1.85-1.95 GHz. The multi-beam operation of base station antennas for mobile communications is widely used to subdivide the angular sector of service into the narrower subsectors, each of which is served by own base station. The 12-element linear array has been designed with the controlled beam tilt from 13° to 19°, since the main beam should be directed to the area below base station. A novel modification of cast metal crossed dipoles is used as an array element. To obtain stable 90° half power beamwidth the special metal walls around the dipoles have been introduced into design as well as the vertical walls at the edges of the plane reflector behind the dipoles. Due to these modifications proposed linear array shows high characteristics: measured beamwidth in horizontal plane by the tilt of beam up to 19° is on average 87°, the beamwidth in vertical plane is 7.3°, gain is 16.3 dB, the reflection loss is less than -17 dB, the isolation is better than -29 dB, the cross-polarization component is less than -17 dB. The suggested linear array has compact dimensions and it is designed for installation in the multi-beam base station antenna array.