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Directional Antennas
Directional antennas come in many different styles and shapes. An antenna does not offer any added power to the signal, and instead
simply redirects the energy it received from the transmitter. By redirecting this energy, it has the effect of providing more energy in
one direction, and less energy in all other directions. As the gain of a directional antenna increases, the angle of radiation usually
decreases, providing a greater coverage distance, but with a reduced coverage angle. Directional antennas include yagis, patch
antennas, and parabolic dishes. Parabolic dishes have a very narrow RF energy path and the installer must be accurate in aiming
these at each other.
Figure 2 Directional Patch Antenna
Figure 3 YAGI Antenna
28 – 80 degrees at 2.4 GHz
68 – 78 degrees at 900 MHz
Directional Yagi
Diversity Antenna Systems
Diversity antenna systems are used to overcome a phenomenon known as multipath distortion of multipath fading. It uses two
identical antennas, located a small distance apart, to provide coverage to the same physical area.
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