Directional (Yagi/LPDA) or Omni Antenna - Which one is right for you?

Deciding between Yagi- and Omni Directional Antennas

Written in conjunction with The Poynting Group.

The choice between omni-directional and directional antennas is not always simple. We will explain the key differences experienced when using a uni-directional (aka ‘directional’) antenna versus an omni-directional (aka ‘omni’) antenna.

The Omni Antenna

The essence of an omni antenna is that it provides similar reception in all directions, much like a normal round light bulb. This can be both an advantage and disadvantage, as discussed below:

Benefits

• Can receive signals from virtually all directions. For example, a mobile or LTE-enabled router can roam across various cellular mobile base stations in any direction.
• If one cellular base station (tower) is congested or faulty, the possibility of receiving another site is higher compared to a directional antenna.
• Better probability of maintaining good connection stability in various situations.
• Easier to install and does not require realignment/adjustment when the network changes (new sites, network problems, etc.).

Disadvantages

• Potentially receives interference from all directions, which could degrade the user experience.
• Overall gain is lower, resulting in lower peak throughput compared to a directional antenna.

Directional Antennas

The Yagi Antenna Directional or LPDA antennas focus their gain (reception) in one direction, much like a flashlight does to a light bulb. This makes them suitable in certain scenarios:

Benefits

• Improved signal from the target direction through directivity gain, which acts like amplification.
• Reduced gain from other directions, hence suppression of interference (unwanted signals).
• Improved Carrier to Interference Ratio (C/I), beneficial in cellular and other radio frequency (RF) systems reception.
• Better signal reception stability, as long as the target base station (tower) is not congested or faulty.

• When the target base station performs poorly, you may need to realign the antenna.
• Implementation can be more complicated as the antenna must be directed towards the target base station or transceiver.
• If the cellular base station (tower) becomes congested or faulty, the impact will be more severe compared to an omni antenna.
• Choosing which site to direct the antenna towards is not always easy.

In Essence

Omni Antenna: Offers better overall reliability, especially in scenarios involving cellular site outages and congestion. However, it provides slower throughput and is less efficient in difficult areas, making it a better option for urban/suburban areas with sufficient cellular base station sites.

Directional Antenna: Provides better throughput, but performance can significantly drop if the cellular base station is congested or out of service. It is beneficial in difficult areas, mostly distant rural areas, as it reduces interference from other sites not in the target direction, improving the C/I ratio and thus throughput.

Implementation of Both in a MIMO Router: Combining both omni and directional antennas in a MIMO configuration can help reduce the disadvantages of each option.

This article was brought to you in collaboration with The Poynting Group. For more information on Poynting Antennas, contact 012 657 0050 or email us.

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