electrical tilt in GSM antenna

I would assume a dipole group with phase shifted feed.

electrical tilt is preferred over mechanical tilt as ET causes regular and uniform changes in its pattern. Also remember this summary:

With the mechanical tilt, the coverage area is reduced in central direction, but the coverage area in side directions are increased.

With the electrical tilt, the coverage area suffers a uniform reduction in the direction of the antenna azimuth, that is, the gain is reduced uniformly.

source:http://www.telecomhall.com/what-is-a...to-use-it.aspx