Antennas are the heart of a wireless system. The unit of measurement for antennas is gain, measured in decibels. Higher gain antennas are able to transmit signals farther or receive weaker signals. Increasing the gain of an antenna is the most efficient way to improve signal strength in a wireless system.
Antennas For Wireless Internet Networks
Antennas are typically the most important part of a wireless Internet link or wireless system due to several factors:
1. Adding antenna gain improves the link in two directions, send and receive while adding radio power only helps in the transmit direction.
2. Using the narrowest antenna beam-width will reduce noise on a wireless link. For example, a sector is almost always a better choice than an omni antenna.
3. The larger an antenna, the more gain it will produce and the more directional it will be.
Wireless and WiFi
Here are some more important information about wireless and WiFi antennas:
dBi is used to specify antenna power gain. It is referenced to the 100% efficient isotropic radiator case or "deciBels above isotropic reference".
dBd, also used to reference antenna gain, refers to deciBels above dipole. A 100% efficient isotropic radiator consists of a point source (radio) with power equally spread in all directions with perfect efficiency (all the power at the input of the antenna is radiated out equally).
As dBi (antenna gain) is increased, the unit area becomes smaller, effectively concentrating the same amount of radiated power.
Directivity is great for outdoor wireless because it increases gain and “filters” noise.
Directivity depends on the effective surface area of the antenna. The larger the area, the more potential directivity.
Directivity of an antenna and its efficiency determine its gain.
Achieving antenna gain involves additive phasing of electrical waves. Antenna arrays and aperture reflectors are often used as a way to achieve this.
Have more questions about antennas? Attend one of our training seminars and learn more or call our knowledgeable sales staff at 855-WISP-PRO.