Antenna and Accessory FAQs

The following antenna types are used:

• Usage: communication antennas, television antenna, radar antenna
• Working frequency band: short wave antenna, ultra-short wave antenna, microwave antenna
• Direction: omnidirectional antenna, directional antenna
• Appearance: wire antenna, mesh antenna

Huawei often uses the following antennas:

• Indoor antenna
  • Indoor omnidirectional/directional ceiling mount antenna

  • Indoor directional antenna

  • Indoor SMA antenna

• Outdoor antenna
  • 2.4G&5G omnidirectional antenna

  • 2.4G&5G directional antenna

  • Backhaul antenna

The following WLAN components are commonly used:

• Splitter: divides a signal into two or more signals.

• Coupler: divides a signal on a port into uneven signals on multiple output ports.

• Attenuator/Load: reduces the amplitude or power of a signal without appreciably distorting its waveform. The load is a special attenuator with unlimited attenuation. The load connects to the unused output radio port, preventing radio interference.

• Combiner: combines radio signals of multiple systems over one channel and distributes receive signals over one channel to ports of each system without interference. Combiners are classified into single-band combiners and multiple-channel combiners.

• Connector:
  • N-type connector

  • SMA connector

• Protection components
  • Surge protection device

  • Other protection components: optical fiber tube, ground cable, and waterproof tape

Antennas are passive components. They can only collect wireless signals, but cannot amplify signals. A smaller antenna angle indicates a higher gain.

The antenna coverage depends on the antenna angle and gain. The antenna coverage area is similar to a taper.

No, the gain is a fixed attribute of an antenna and cannot be adjusted.

A multi-band combiner must support proper working frequency bands, provide filtering functions, and it is recommended that the isolation between ports should be greater than 80 dB. A proper isolation degree reduces interference between different systems.

Antennas, feeders, splitters, combiners, and couplers.

Antenna tilt: angle between the antenna emission direction and the horizontal direction.

Field angle: angle between the two directions opposed to each other over the beam axis for which the luminous intensity is half that of the maximum luminous intensity.

The field angle often refers to the beam angle.

The indoor AP applies to middle-scale deadzone coverage or important public places such as hotels, airports, and conference centers. The indoor AP does not apply to networks demanding high capacity.

The following figure shows the indoor distribution system.

The following figure shows hotel WLAN coverage scenario.

The outdoor AP applies to squares, residential areas, schools, dormitories, campuses, open areas with dense population, commercial streets that have high requirements for wireless data services.

The following figure shows campus WLAN coverage scenario.

To allow the installation of an antenna, a pole must be no thinner than 2.5 mm. A 50 mm diameter pole made of round steel is usually used.

Determine the installation position of antennas based on the Line of Sight (LOS), and the installation position of APs based on power supply modes, data to be transmitted, and environmental conditions. Determine the feeder length according to the distance between APs and antennas.

The longer the feeder, the weaker the signal strength within the antenna coverage scope. Use feeders as short as possible to connect antennas and APs.

The required bend radius of radio cables is as follows: RG-8U feeders longer than 150 mm, 1/2-inch feeders longer than 50 mm, and 7/8-inch feeders longer than 250 mm. (1 inch = 25.4 mm.)

• Azimuth is the angle from the north plane to the antenna plane clockwise.
• Downtilt is the angle between the antenna emission direction and the horizontal direction.

Figure 15-1 Antenna angles

Dual-polarized and single-polarized antennas differ in the following aspects:

Transmit angle:

• In mountainous or plain villages of open regions, signals of mobile phones easily match vertical-polarized signals. Therefore, vertical-polarized antennas provide better coverage effect than non-vertical-polarized antennas.
• In urban areas, electromagnet waves are reflected many times among buildings. Metal objects and metal oxide coated glass in and outside buildings may cause the polarization direction to change. Vertical-polarized antennas (single- and dual-polarized) and ±45° dual-polarized antennas provide similar coverage capabilities.

Receive angle:

• Single-polarized antenna: receives and transmits radio signals using two separate antennas. Radio signals are transmitted and received at the horizontal or vertical direction. Therefore, a large installation space and large maintenance workload are required.
• Dual-polarized antenna: receives and transmits radio signals using one antenna. The transmit direction of radio signals is vertical to the receive direction.

Antenna dimension: Dipoles of a dual-polarized antenna in different polarization directions are sufficiently isolated even if the dipoles are overlapped. Therefore, a dual-polarized antenna is no larger than a single-polarized antenna.

Antennas are selected depending on the transmission distance, required bandwidth, and number and locations of peer transmission points (for determining the antenna angle). Therefore, antenna selection is irrelevant to relay.