ProSoft Technology RLX2-IHNF-WC - Manual (Page 184)

RLX2 Industrial Hotspot Series
Page 184 of 212 ProSoft Technology, Inc.
June 15, 2015
An antenna pattern with equal or nearly equal intensity in all directions is
omnidirectional. In two dimensions, an omnidirectional pattern appears as a circle (in
three dimensions, an omnidirectional antenna pattern would be a sphere, but no
antenna has true omnidirectional pattern in three dimensions). An antenna is
considered omnidirectional if one of its two dimensional patterns, either azimuth or
elevation pattern, is omnidirectional.
Beamwidth is an angular measurement of how strongly the power is concentrated in a
particular direction. Beamwidth is a three dimensional quantity but can be broken into
two-dimensional slices just like the antenna pattern. The beamwidth of an
omnidirectional pattern is 360 degrees because the power is equal in all directions.
Antenna Gain
Antenna gain is a measure of how strongly an antenna radiates in its direction of
maximum radiation intensity compared to how strong the radiation would be if the
same power were applied to an antenna that radiated all of its power equally in all
directions. Using the antenna pattern, the gain is the distance to the furthest point on
the pattern from the origin. For an omnidirectional pattern, the gain is 1, or equivalently
0 dB. The higher the antenna gain is, the narrower the beamwidth, and vice versa.
The amount of power received by the receiving antenna is proportional to the
transmitter power multiplied by the transmit antenna gain, multiplied by the receiving
antenna gain. Therefore, the antenna gains and transmitting power can be traded off.
For example, doubling one antenna gain has the same effect as doubling the
transmitting power. Doubling both antenna gains has the same effect as quadrupling
the transmitting power.
Antenna Polarity
Antenna polarization refers to the direction in which the electromagnetic field lines
point as energy radiates away from the antenna. In general, the polarization is elliptical.
The simplest and most common form of this elliptical polarization is a straight line, or
linear polarization. Of the transmitted power that reaches the receiving antenna, only
the portion that has the same polarization as the receiving antenna polarization is
actually received. For example, if the transmitting antenna polarization is pointed in the
vertical direction (vertical polarization, for short), and the receiving antenna also has
vertical polarization, the maximum amount of power possible will be received. On the
other hand, if the transmit antenna has vertical polarization and the receiving antenna
has horizontal polarization, no power should be received. If the two antennas have