Types Of Antennas For Wlan - ZyXEL Communications P-320W User Manual

P-320W User's Guide

Types of Antennas For WLAN

There are two types of antennas used for wireless LAN applications.
• Omni-directional antennas send the RF signal out in all directions on a horizontal plane.
The coverage area is torus-shaped (like a donut) which makes these antennas ideal for a
room environment. With a wide coverage area, it is possible to make circular overlapping
coverage areas with multiple access points.
• Directional antennas concentrate the RF signal in a beam, like a flashlight. The angle of
the beam width determines the direction of the coverage pattern; typically ranges from 20
degrees (less directional) to 90 degrees (very directional). The directional antennas are
ideal for hallways and outdoor point-to-point applications.
Positioning Antennas
In general, antennas should be mounted as high as practically possible and free of
obstructions. In point-to –point application, position both transmitting and receiving antenna
at the same height and in a direct line of sight to each other to attend the best performance.
For omni-directional antennas mounted on a table, desk, and so on, point the antenna up. For
omni-directional antennas mounted on a wall or ceiling, point the antenna down. For a single
AP application, place omni-directional antennas as close to the center of the coverage area as
possible.
For directional antennas, point the antenna in the direction of the desired coverage area.
210 Appendix G Antenna Selection and Positioning Recommendation