Types of WiFi antennas

The antennas used with 2.4 GHz wireless LAN equipment can be sorted by the shape of their coverage. Omnidirectional antennas radiate evenly around a vertical axis and suit access points that must serve clients in every horizontal direction. The familiar rubber-duck whip on a router is a short vertical antenna of this kind, and stacking several elements into a collinear array raises gain while keeping the all-round pattern, flattening it into a disc that reaches farther across a floor but less above and below.

Directional antennas trade wide coverage for reach in one direction. Panel and patch antennas are flat planar designs that radiate from one face, convenient for mounting on a wall to cover a room or to feed a point-to-point hop. The Yagi array gives moderate-to-high gain in a compact in-line form, and the home-built biquad, a double-square loop over a reflector, is a popular do-it-yourself directional antenna for the band. For the longest links, parabolic dishes and grid reflectors focus energy into a narrow, high-gain beam.

Choosing among these depends on the job. Indoor coverage of an area around an access point favours an omnidirectional or a wall-mounted panel. Bridging two buildings or reaching a distant station favours a directional antenna aligned along the path, with both ends sharing the same polarization. Because higher gain narrows the beam, very directional antennas need careful aiming to perform as intended.

Frequently asked questions

What is a rubber-duck antenna?

It is the short, flexible omnidirectional whip antenna fitted to many access points and adapters, giving all-round coverage with modest gain.

What is the difference between a panel and a Yagi antenna?

Both are directional. A panel is a flat planar antenna radiating from one face, while a Yagi uses a line of elements to form its beam; the Yagi is often more compact for a given gain.

Why must directional antennas be aimed carefully?

Higher gain comes with a narrower beam, so a small misalignment can move the target out of the strongest part of the pattern and weaken the link.