Sector antenna can be described as directional microwave antennas having a radiation pattern with a sector shape. This word ‘sector’ is utilized geometrically. Some fraction of a circle’s circumference measured in arc degrees.
120 degrees, 90 degrees, and 60 degrees, are typical, usually with few degrees more to make sure overlap occurs and also mounted in form of multiples whenever there is a need for a full-circle or wider coverage. The most important utilization of the sector antenna is for cell phone sites. Also, they are utilized for the limited range distances falling between 4 and 5 km.
In this article, we will explain everything elated to sector antennas. We will also state the differences between the sector antenna and omni antenna.
What Does a Sector Antenna Mean?
Sector antennas can be called sector panels, and they are directional antennas that serve outdoor applications. Most times, they are utilized by base stations, and they could be seen, as well as hung on the towers of cell phones. Also, they are narrow, long antennas that have high gains.
Furthermore, the sector antennas are made of different dipoles that are place in-front of shaped reflectors. Also, the reflector’s shape and size helps in determining their antennas’ performance. Usually, this reflector is flat, and it comes with ridges along with other features present along its edges.
Most times, t5he sector antenna is categorized by its 3-dB azimuth plane width. Also, they are available in the 120 degree, 90 degree, and 60 degree directionality. These sectors are applied higher up inside air and its deployment height selects the necessary antenna because thus affects the antenna’s range and gain.
More on Sector Antenna
The sector antenna’s main reflection screen is made of Aluminum and this antenna features a radomes. This radome is made from fiberglass material and this ensures that the components remain in the antenna safe. It also ensures the antenna can withstand any harsh weather condition. The sector antenna is used for cellular communication extensively. The greatest use of the antenna is for the base station sites of cell phones.
The sector antenna’s coverage area can be determined by the radiation pattern projection on the ground area. This could be adjusted by altering the antenna’s down-tilt angle. There are models whereby this is mechanically done by adjusting the antenna’s tilt manually with the adjustable mounting bracket.
For sector antennas that are more recent, it is possible to tilt the pattern electronically. This is done through the phase shifters present inside the feed of the antenna’s dipole antennas. You can adjust this with remote control circuits from the ground, getting rid of the need to get a technical to get to the antenna tower. In order to get coverage in 360 degrees, you should use multiple sector antennas and you have to mount them back to back.
The Design of the Sector Antenna
At the sector antenna’s bottom region, you will find RF connectors. These are meant for the coaxial cable as well as adjustment mechanisms. Also, for the outdoor placement, its primary reflector is manufactured from aluminum, and all of its internal parts are all housed in fiberglass radomes enclosures. This is to ensure that its operation remains stable no matter the weather condition.
For outdoor antennas, grounding is very necessary. This is to ensure that all the metal components are DC grounded. The narrow long form of the antenna provides it with fan shaped radiation pattern. When in horizontal direction, it is wide, and when it is vertical, it is relatively narrow.
More on Sector Antenna Design
According to your depicted radiation pattern, typical antennas utilized in the three sector base stations feature 66 degrees of the horizontal bandwidth. What this means is that the strength of the signal present at the ±33 degree directions is 3 dB down or half its usually peak value when at the middle or center.
Also, when it is at the ±60 degree directions, then we suggest that it is a border of the sector and the gain of the antenna is negligible. The vertical bandwidth isn’t wider than 15 degrees. This means 7.5 degrees in every direction. In contrast to the antennas that serve commercial broadcasting – television, FM, and AM for example – that has to achieve line of sight over many kilometer s or miles, there’s always a downward downtilt or beam tilt top ensure the base station will be able to cover the immediate area effectively and not lead to any RF interference to the distant cells.
This coverage area that is determined by the radiation pattern’s projection onto the ground could be adjusted by altering the pattern’s downtilt. For some models, this could be mechanically done through adjusting the antenna’s tlt manually with the help of the adjustable mounting brackets.
For sector antennas that are more recent, it is possible to tilt the pattern electronically. This is done through the phase shifters present inside the feed of the antenna’s dipole antennas. You can adjust this with remote control circuits from the ground, getting rid of the need to get a technical to get to the antenna tower.
How to Use the Sector Antenna
In order to widen as well as increase the area for coverage, and your served clients, different sector antennas can be installed on one supporting structure, for example, a mast or tower.
This type of construction is usually referred to as the sectorized antenna. Although, there are times whereby sector antennas are utilized also. This features different secular antennas that are angularly separated.
Immediately the antenna has been attached to the supporting structure, it must be positioned. When we say positioning, we mean not just setting the correct azimuth or direction, but setting the right downtilt too. When you restrict emitted energy into narrow vertical coverage and sub-circular arcs, this design will make proper utilization of transmitter equipment with very low power.
Although there is a limited absolute range, the configuration permits great data rates (the transfer of digital information, calculated in bits per second, which is at times given as the full minus error-correction overheads), as well as great signal consistency in the coverage area.
More Tips on Using the Sector Antenna
Before positioning, lighting and grounding protection are very necessary. All the supporting constructions usually include lightning rods. Downtilt setting strategies that are properly chosen could reduce the network’ overall interference. Furthermore, a downtiliting strategy that is too aggressive would result in general coverage loss because the cells are not overlapping.
You can use downtiliting for solving some issues. These include too large cells, or local interference issues. The beam width is slightly reduced by electrical tilting.
Take note that more vertical antennas would be less visible compared to mechanically tiled ones. The utilization of just electrical tilt excluding the mechanical tilt would therefore be a great choice for different aesthetic reasons that are very significant for operators that seek the acceptance of the integrated antennas present in the visible locations.
Sector Antennas vs Omni Antennas: What’s the Difference?
In this section, we will be comparing the sector antennas with the omni antenna. We will also be explaining the differences between both antenna types.
Often, people are inquisitive about the differences between the sector antennas and the omnidirectional or omni antennas. Both antennas look very similar, bit their functions are quite different. Below is a complete breakdown of the way they function. This allows you to determine the best option for your application.
From the name, the omni-directional antennas help in transmitting and receiving uniform signals through a pattern of 360 degrees. The omni antenna’s radiation pattern looks like a donut having reduced coverage which is immediately above and below the antenna, as well as expanded coverage while you move away further from this antenna.
Because omni antennas have the ability to transmit as well as receive signals in all direction, they are usually utilized by WISPS having access points. These Omnis are appropriate for utilization in the rural environments whereby the initial subscriber counts could be low.
Sector antennas are grouped as the directional microwave type of antennas. In contrast to Omnis, the sector antennas would only transmit as well as receive the concentrated signals in just one direction. Also, the WISPs usually utilize the sector antennas to serve point to multipoint base station applications. Also, they are better suited to serve dense environments whereby there are higher subscriber counts.
Conclusion
In summary, sector antennas can be called sector panels, and they are directional antennas that serve outdoor applications. Most times, they are utilized by base stations, and hung on the towers of cell phones.
Also, they are narrow, long antennas that have high gains. In order to widen as well as increase the area for coverage, different sector antennas can be installed on one supporting structure, for example, a mast or tower. This type of construction is usually referred to as the sectorized antenna. Comparing the sector antenna and omni antennas, both antennas look very similar, but their functions are quite different
