Pattern distortion of mobile radio base station antennas by antenna masts and roofs

We analyze the influence of antennamasts, mounting structures, and roofs on the radiation pattern of base station antennas tor mobile communications. The distortions in the horzontal radiation pattern of omni-antennas caused by the mast can be up to 10dB, but the mast conductivity has only minor effects. The antenna mast also leads to a reduction in the sidelobe attenuation of the vertical radiation pattern of an array antenna. Mounting structures (horizontal metallic bars) have only a very small influence on the pattern. Finally, the rooftops on which the antennas are mounted can also lead to very strong (>10dB) distortions of the radiation pattern. These effects must be considered in the cell planning for mobile radio communications networks.