ZyXEL Access Point G1000 v2 91-005-124001B Manual Do Utilizador

ZyXEL G-1000 v2 User’s Guide

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An antenna couples RF signals onto air. A transmitter within a wireless device sends an RF 
signal to the antenna, which propagates the signal through the air. The antenna also operates in 
reverse by capturing RF signals from the air. 

Choosing the right antennas and positioning them properly increases the range and coverage 
area of a wireless LAN. 

An antenna in the frequency of 2.4GHz (IEEE 802.11b) or 5GHz(IEEE 802.11a) is needed to 
communicate efficiently in a wireless LAN. 

A radiation pattern is a diagram that allows you to visualize the shape of the antenna’s 
coverage area. 

Antenna gain, measured in dB (decibel), is the increase in coverage within the RF beam width. 
Higher antenna gain improves the range of the signal for better communications. 

For an indoor site, each 1 dB increase in antenna gain results in a range increase of 
approximately 2.5%. For an unobstructed outdoor site, each 1dB increase in gain results in a 
range increase of approximately 5%. Actual results may vary depending on the network 
environment. 

Antenna gain is sometimes specified in dBi, which is how much the antenna increases the 
signal power compared to using an isotropic antenna. An isotropic antenna is a theoretical 
perfect antenna that sends out radio signals equally well in all directions. dBi represents the 
true gain that the antenna provides.