Brocade Enterprise Wireless LAN Antenna Specification Guide, Version 1.5 - Manual (Page 18)

6 Enterprise Wireless LAN Antenna Specification Guide
53-1001881-01
Antenna selection criteria
1
Antenna type
Panel
A panel antenna is a flat antenna mounted to a wall or other vertical surface and radiates RF
energy (radio waves) directionally away from the wall. They usually have gain greater than 5 dBi and
are not suitable for omni-directional situations. Ideally suited for long hallways.
Patch
A patch antenna is a flat antenna mounted on the ceiling but whose pattern is omni-directional.
Most of the energy goes out horizontally to the sides of the antenna and equal in all directions.
Dipole
A dipole antenna is a tubular antenna that can be either a pipe shape, a straight flexible rod or a
paddle. This antenna has an omni-directional pattern when placed in a vertical position. It usually
has 2 dBi of gain.
Dipole array
Essentially a dipole, a dipole array is two or more dipoles that are placed one on top of the other,
requiring a longer tube to hold them. The advantage of a dipole array is that it has higher gain.
Parobolic grid
A paraobolic grid antenna is a very directional, dish-like antenna. Its parabolic reflector focuses the
RF energy like a flashlight. Most of the time the radiating element is a dipole, but when combined
with the dish, it becomes very directional with gain up to 24 dBi. Usually used in long point-to-point
systems.
Yagi
A yagi antenna is a antenna that has an internal structure resembling that of typical antennas used
for TV reception (a series of rods perpendicular to a main rod, making a triangular shape). This is a
directional antenna with less gain than the PGA, typically around 13 dBi. It may be used in either
point-to-point situations, or to cover a very long, narrow area in point-to-multi-point situations.
Antenna performance characteristics
Frequency
The frequency band within which the antenna performs at the stated specifications
Gain (dBi)
The relative amplification of the antenna with respect to an equivalent isotropic antenna,
expressed on the decibel logarithmic scale.