Electrical tilt (which was introduced in Second-generation cellular antennas) where the beam is 'tilted' by altering the signal phasing. This solution offers an undistorted azimuth beam plus the distinct advantage of tilting all lobes (main, rear and side) to the same measure, thus controlling interference in all directions. It was somewhat limited, being available only in discrete steps. Hence in The development of the third-generation cellular antenna, which features "adjustable electrical tilt" which allows cellular operators to continuously tilt the antenna, enabling optimisation of coverage and interference reduction without compromise. This technology has proved particularly useful for suppressing detrimental side lobe radiation. The latest antenna development by Radio Frequency Systems is the introduction of remote electrical tilt. This new technology extends the convenience of variable electrical tilt by relocating the tilt adjustment facility from the antenna body to the tower base or the network management centre. In an age where fast and efficient network tuning is becoming critical, remote tilt technology will provide substantial site optimisation benefits.

Answered by Alok Gupta , an ibibo Guru, at 5:14 PM on April 24, 2009

Hi this is R.S.A.

The evolution of the antenna in the development of cellular networks has been critical. Although handset technology, base station design, signal conditioning and multiplexing techniques are all important issues, it is advances in cellular antenna design that have underpinned many of the industry's major milestones.
During its rapid deployment of cellular networks, China has embraced the full range of antenna designs available over the past half-decade. Today, with the imminent deployment of next-generation networks based on both GSM and CDMA, the cellular antenna is still developing.

The earliest cellular antennas were fairly simple radiation platforms such as omnis, corner reflectors and panel antennas. The onset of digital GSM networks and increased subscriber/network demands led to the need for entirely new antenna systems. Network planners required antennas with improved flexibility, more precise cell coverage and reduced total cost, spawning a five-stage antenna development during the 1990s.

The first generation of antenna featured tilt. Mechanically tilting the antenna a few degrees from the vertical provides a coarse means of modifying the antenna's service area. Yet traditional mechanical tilt brought with it a number of problems. Effective only in the forward direction, it can distort the azimuth beam and launch rear lobes upward. It also has no effect on side radiation, a source of multi-path and co-channel interference.

Second-genera tion cellular antennas addressed the shortcomings of mechanical tilt by the introduction of electrical tilt, where the beam is 'tilted' by altering the signal phasing. This solution offers an undistorted azimuth beam plus the distinct advantage of tilting all lobes (main, rear and side) to the same measure, thus controlling interference in all directions.

Good tactical control of beam tilt is an increasingly crucial factor for system operators, who need to trim cell coverage to suit an ever-changing cell terrain, shape and density. The early mechanical and electrical tilt technologies provided system planners and operators with antenna tilt that was somewhat limited, being available only in discrete steps.

Answered by Rsashwin , an ibibo Citizen, at 12:54 PM on April 24, 2009