Sector antenna

60°, 90° and 120° designs are typical, often with a few degrees 'extra' to ensure overlap and mounted in multiples when wider or full-circle coverage is required (see photos below).

For its outdoor placement, the main reflector screen is produced from aluminum, and all internal parts are housed into a fiberglass radome enclosure to keep its operation stable regardless of weather conditions.

Unlike antennas for commercial broadcasting - AM, FM and television for example - which must achieve line-of-sight over many miles or kilometers, there is usually a downward beam tilt or downtilt so that the base station can more effectively cover its immediate area and not cause RF interference to distant cells.

In more recent sector antennas the pattern can be electronically tilted, by adjustable phase shifters in the feed of the individual dipole elements.

These are adjusted by a remote control circuit from the ground, eliminating the need for a technician to climb the antenna tower.

To increase or widen the coverage area, and thus the number of served clients, several sector antennas are installed on the same supporting structure, e.g. tower or mast.

By restricting emitted energy to a sub-circular arc and narrow vertical coverage the design makes efficient use of relatively low power transmitter equipment.