Introduction to Wi-Fi Wireless Antennas

Upgrading Your Router Antenna May Improve Your Wi-Fi Network

Close-Up Of Wireless Router By Window
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Wi-Fi wireless networking works by sending radio transmissions on specific frequencies where listening devices can receive them. The necessary radio transmitters and receivers are built into Wi-Fi enabled equipment such as routers, laptops, and phones. Antennas are key components of these radio communication systems, picking up incoming signals or radiating outgoing Wi-Fi signals. Some ​Wi-Fi antennas, particularly on routers, are mounted externally, while others are embedded inside the device's hardware enclosure.

Antenna Power Gain

The connection range of a Wi-Fi device depends greatly on its antenna's power gain. A numeric quantity measured in relative decibels (dB), gain represents the maximum effectiveness of an antenna compared to a standard reference antenna. Industry manufacturers use one of two different standards when quoting gain measures for radio antennas:

  • dBi refers to decibels relative to an isotropic reference antenna.
  • dBd refers to decibels relative to a dipole reference antenna

Most Wi-Fi antennas use dBi as their standard measure rather than dBd. Dipole reference antennas work at 2.14 dBi, which corresponds to 0 dBd. Higher values of gain indicate an antenna capable of working at higher levels of power, which usually results in greater range.

Omnidirectional Wi-Fi Antennas

Some radio antennas are designed to work with signals sent out and received from all directions. These omnidirectional antennas are commonly used on Wi-Fi routers and mobile adapters — devices that must support connections from multiple directions. Factory Wi-Fi gear often uses basic dipole antennas of the so-called rubber duck design, a helix shape sealed in a protective jacket of rubber or plastic that protects the antenna, similar to those used on walkie-talkie radios. These have a gain between 2 and 9 dBi.

Directional Wi-Fi Antennas

Because the power of an omnidirectional antenna must be spread across 360 degrees, its gain measured in any one direction is lower than directional antennas that focus more energy in one direction. Directional antennas are typically used to extend the range of a Wi-Fi network into hard-to-reach corners of buildings or other specific situations where 360-degree coverage is not needed.

Cantenna is a brand name of Wi-Fi directional antennas. The Super Cantenna supports 2.4 GHz signaling with a gain ​of up to 12 dBi and a beam width of about 30 degrees, suitable for indoor or outdoor use. The term cantenna also refers to generic do-it-yourself antennas using a simple cylindrical design.

A Yagi (more properly called Yagi-Uda) antenna is another type of directional radio antenna that can be used for long-distance Wi-Fi networking. Because they are extremely high gain, usually 12 dBi or higher, these antennas are typically used to extend the range of outdoor hotspots in specific directions or to reach an outbuilding. Do-it-yourselfers can make Yagi antennas, although the process requires more effort than making cantennas.

Upgrading Wi-Fi Antennas

Wireless networking problems caused by weak signal strength can sometimes be solved by installing upgraded Wi-Fi radio antennas on the affected equipment. On business networks, professionals typically perform a comprehensive site survey to map the Wi-Fi signal strength in and around office buildings and strategically install additional wireless access points where needed. Antenna upgrades can be a simpler and more cost-effective option for fixing Wi-Fi signal problems, particularly on home networks.

Consider the following when planning an antenna upgrade strategy for a home network:

  • Some Wi-Fi gear does not support aftermarket antenna upgrades. Consult the manufacturer's documentation.
  • Upgrading a router's omnidirectional antennas can improve connectivity with all devices in the home and sufficiently resolve basic signal issues. Upgrading client devices only benefits each one individually.
  • Evaluate both gain and directional radius support properties of antennas when choosing one. Software packages that map Wi-Fi signal strength in a home are available to use for planning.

Wi-Fi Antennas and Signal Boosting

Installing aftermarket antennas on Wi-Fi equipment increases the effective range. However, because radio antennas only help concentrate and direct signals, the range of a Wi-Fi device is ultimately limited by the power of its radio transmitter rather than only its antenna. For these reasons, signal boosting a Wi-Fi network may be necessary and usually is accomplished by adding repeater devices that amplify and relay signals at intermediate points between network connections.