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5 Antenna Types You Must Know

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satellite antenna

Do you know the antenna you are about to use or buy? For some customers in need, they don't know how to choose the right antenna. Today, as a professional satellite antenna manufacturer, we will show you five types of antennas that you must know, which is very important.

5 AntennasYou Must Know

The five antennas we will discuss next are distinguished according to the radiation angle. Understanding their characteristics and functional effects plays a very important role in your choice to buy and use antennas. These five antennas are omnidirectional antennas, directional antennas, mechanical antennas, electrically adjustable antennas and dual-polarized antennas.

Omnidirectional Antenna

An omnidirectional antenna, that is, it shows uniform radiation in 360° on the horizontal pattern, which is commonly referred to as non-directional, and appears as a beam with a certain width on the vertical pattern. In general, the smaller the lobe width, The greater the gain. The omnidirectional antenna is generally used in the mobile communication system with the station type of the suburban district system, and the coverage is large.

Directional Antenna

Directional antennas show radiation in a certain angular range on the horizontal pattern, which is usually called directional, and show a beam with a certain width on the vertical pattern. Like omnidirectional antennas, the smaller the lobe width , The greater the gain. Directional antennas are generally used in urban cell-based stations in mobile communication systems, with small coverage, high user density, and high frequency utilization.

Different types of base stations can be established according to the requirements of the networking, and different types of base stations can choose different types of antennas according to their needs. The selection is based on the above technical parameters. For example, an omnidirectional station uses an omnidirectional antenna with basically the same gain in each horizontal direction, while a directional station uses a directional antenna with a significant change in the horizontal gain. Generally, an antenna with a horizontal beam width B of 65° is selected in the urban area, and an antenna with a horizontal beam width B of 65°, 90° or 120° is selected in the suburbs (depending on the station configuration and local geographic environment), while in the countryside It is the most economical to choose an omnidirectional antenna that can achieve large-scale coverage.

Mechanical Antenna

The so-called mechanical antenna refers to a mobile antenna that uses mechanical adjustment of the downward tilt angle.

After the mechanical antenna is installed vertically to the ground, if the network is optimized, the position of the bracket on the back of the antenna needs to be adjusted to change the inclination angle of the antenna. During the adjustment process, although the coverage distance in the main lobe direction of the antenna changes significantly, the amplitudes of the vertical and horizontal components of the antenna remain unchanged, so the antenna pattern is easily deformed.

Precautions

Practice has proved that the best downtilt angle of the mechanical antenna is 1°-5°; when the downtilt angle changes from 5°-10°, the antenna pattern is slightly deformed but does not change much; the current downtilt angle is 10°-15 When ° changes, the antenna pattern changes greatly; when the mechanical antenna is tilted down by 15°, the shape of the antenna pattern changes greatly, from a pear shape when there is no downward tilt to a spindle shape. Obviously shortened, but the entire antenna pattern is not all in the local base station sector, and signals from the base station will also be received in adjacent base station sectors, causing serious intra-system interference.

Maintenance of mechanical antenna

In daily maintenance, if you want to adjust the downward tilt angle of the mechanical antenna, the entire system must be shut down, and monitoring cannot be performed while adjusting the antenna tilt angle; it is very troublesome to adjust the downward tilt angle of the mechanical antenna, and generally requires maintenance personnel to climb to the antenna location to make adjustments. ; The downtilt angle of the mechanical antenna is the theoretical value calculated by the computer simulation analysis software, which has a certain deviation from the actual best downtilt angle; the step of adjusting the tilt angle of the mechanical antenna is 1°, and the third-order intermodulation index is -120dBc .

ESC Antenna

The so-called electrically adjustable antenna refers to a mobile antenna that uses electronic adjustment of the downward tilt angle.

The principle of electronic downtilt is to change the phase of the collinear array antenna element, change the amplitude of the vertical component and the horizontal component, and change the field strength of the composite component, so as to make the vertical directivity diagram of the antenna downward. Because the field strength of each direction of the antenna increases and decreases at the same time, it is ensured that the antenna pattern does not change much after the tilt angle is changed, so that the coverage distance in the main lobe direction is shortened, and at the same time, the entire directional pattern is reduced in the serving cell sector. Area but no interference. Practice has proved that when the downward tilt angle of an electrically adjustable antenna changes from 1° to 5°, its antenna pattern is roughly the same as that of a mechanical antenna; when the downward tilt angle changes from 5° to 10°, its antenna pattern is slightly better than that of a mechanical antenna. There is improvement; when the downward tilt angle is changed between 10°-15°, the antenna pattern changes more than the mechanical antenna; when the mechanical antenna is tilted down 15°, the antenna pattern is significantly different than that of the mechanical antenna. At this time, the antenna The shape of the pattern has not changed much, and the coverage distance of the main lobe direction is significantly shortened. The entire antenna pattern is in the sector of the base station. Increasing the downtilt angle can reduce the coverage area of ​​the sector without causing interference. Such a pattern is What we need, so the use of electrically adjustable antenna can reduce call loss and reduce interference.

Dual-polarized ntenna

Dual-polarization antenna is a new type of antenna technology that combines +45° and -45° polarization directions orthogonal to each other antenna and works in the transceiver duplex mode at the same time, so its most prominent advantage is to save a single directional The number of antennas in the base station; generally, the directional base station (three sectors) of the GSM digital mobile communication network uses 9 antennas, and each sector uses 3 antennas (space diversity, one transmitter and two receivers). If dual-polarized antennas are used, each Only one antenna is required for each sector; at the same time, due to the polarization orthogonality of ±45° in dual-polarized antennas, the isolation between +45° and -45° two antennas can meet the requirements of intermodulation pair antenna isolation Therefore, the space interval between dual-polarized antennas only needs to be 20-30cm; in addition, dual-polarized antennas have the advantages of electrically adjustable antennas. The use of dual-polarized antennas in mobile communication networks is the same as that of electrically adjustable antennas. Reduce call loss, reduce interference, and improve the service quality of the entire network. If a dual-polarized antenna is used, because the dual-polarized antenna does not have high requirements for erection and installation, there is no need to requisition the land to build a tower, only a 20cm diameter iron post is needed, and the dual-polarized antenna is fixed on the iron post according to the corresponding coverage direction That is, it saves capital construction investment, and at the same time makes the layout of the base station more reasonable, and the selection of the base station site is easier.

Conclusion

The above are the five antennas we need to understand, they have different applicable scenarios and usage methods. I hope you can help your business after reading this article. If you are interested, you can read more of our articles to learn more about antennas.

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