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Beam steering is a technique for changing the direction of themain lobe of aradiation pattern.Beam tilt is used inradio to aim the mainlobe of thevertical planeradiation pattern of an antenna below (or above) thehorizontal plane.
Inradio andradar systems, beam steering may be accomplished byswitching theantenna elements or by changing the relativephases of theRF signals driving the elements. As a result, this directs the transmit signal towards an intended receiver. In recent days, beam steering is playing a significant role in5G communication because of quasi-optic nature of 5G frequencies.[1]
The simplest methodbeam tilt is mechanical beam tilt, where the antenna is physically mounted in such a manner as to lower the angle of the signal on one side. However, this also raises it on the other side, making it useful in only very limited situations.
More common is electrical beam tilt, where thephasing between antenna elements is tweaked to make the signal go down (usually) in all directions.[2] This is extremely useful when theantenna is at a very high point, and the edge of the signal is likely to miss the target (broadcast audience, cellphone users, etc.) entirely.
With electrical tilting, front and back lobes tilt in the same direction. For example, an electrical downtilt will make both the front lobe and the back lobe tilt down. This is the property used in the above example where the signal is pointed down in all directions. On the contrary, mechanical downtilting will make the front lobe tilt down and the back lobe tilt up. In almost all practical cases, antennas are only tilted down – though tilting up is technically possible.
The use of purely electrical tilt with no mechanical tilt is an attractive choice for aesthetic reasons which are very important for operators seeking acceptance of integrated antennas in visible locations.
In GSM and UMTS cellular networks, mechanical tilt is almost always fixed whereas electrical tilt can be controlled using remote actuators and position sensors, thus reducing operating expenses. Remote electrical tilt is abbreviated as RET and it is part of the Antenna Interface Standards Group's open specification for the control interface of antenna devices.[3]
Occasionally, mechanical and electrical tilt will be used together in order to create greater beam tilt in one direction than the other, mainly to accommodate unusualterrain. Along withnull fill, beam tilt is the essential parameter controlling the focus ofradiocommunications, and together they can create almost infinite combinations of 3-Dradiation patterns for any situation.
Beam tilt optimization is a network optimization technique used in mobile networks aiming at controlling the inclination of the vertical tilt angle of the antenna in order to optimize a set of network performance indicators.
Different studies in beam tilt optimization[4] focus on Coverage-Capacity Optimization (CCO), for which the goal is to control the beam tilt in order to jointly optimize the radiocoverage andcapacity in the network cells and reduce interference from neighbouring cells.
There exists mainly two types of approaches to beam tilt optimization:
Inacoustics, beam steering is used to direct the audio fromloudspeakers to a specific location in the listening area. This is done by changing the magnitude and phase of two or more loudspeakers installed in a column where thecombined sound is added and cancelled at the required position. Commercially, this type of loudspeaker arrangement is known as aline array. This technique has been around for many years but since the emergence of moderndigital signal processing (DSP) technology there are now many commercially available products on the market. Beam steering and directivity Control using DSP was pioneered in the early 1990s by Duran Audio who launched a technology called DDC (Digital Directivity Control).
Inoptical systems, beam steering may be accomplished by changing therefractive index of themedium through which the beam is transmitted or by the use ofmirrors,prisms,lenses, or rotatingdiffraction gratings. Examples of optical beam steering approaches include mechanical mirror-basedgimbals or beam-director units,galvanometer mechanisms that rotate mirrors,Risley prisms,phased-array optics, andmicroelectromechanical systems using micro-mirrors.
The scope of beam-steering technologies has broadened significantly with innovations that serve both traditional applications and emerging demands in fields such as satellite communication, radar, and 5G networks.[8][9] Traditional methods like parabolic reflectors and phased arrays are now complemented by Reflectarray (RA)[10] and Transmitarray (TA)[11] antennas. These designs serve as high-gain, planar alternatives with advantages in cost, efficiency, and scalability, meeting modern requirements for compact and lightweight systems. One of the latest approaches in beam steering involves Near-Field Meta-Steering (NFMS),[12] which uses phase-gradient metasurfaces placed in close proximity to a feed antenna. This method achieves 3D beam steering by employing compact structures that allow wide-angle control over both elevation and azimuth, proving highly effective for systems where space and profile height are restricted.
Beam steering has also found essential applications in high-speed, interference-free communication for defense and civilian markets. Satellite-based communication systems, for example, require dual-band beam-steering capabilities to handle uplink and downlink data streams simultaneously.[13][8][9] The development of beam-steering antennas for Satellite Communication on the Move (SOTM) systems[13] highlights the need for antennas that are not only efficient but also lightweight, low-profile, and cost-effective. Challenges remain, including addressing cost constraints and achieving higher scanning speeds and wider bandwidths.[13]
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