Circular polarization: Difference between revisions

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Circular polarization may be referred to as ''right'' or ''left'', depending on the direction in which the electric field vector rotates. Unfortunately, two opposing, historical conventions exist. In [[physics]] and [[astronomy]], polarization is defined as seen from the ''receiver'', such as a [[telescope]] or [[radio telescope]]. By this definition, if you could stop time and look at the electric field along the beam, it would trace a helix which is the same shape as the same-handed screw. For example, right circular polarization produces a right threaded (or forward threaded) [[screw]]. In the U.S., [[Federal Standard 1037C]] also defines the handedness of circular polarization in this manner. In [[electrical engineering]], however, it is more common to define polarization as seen from the ''source'', such as from a transmitting antenna. To avoid confusion, it is good practice to specify "as seen from the receiver" (or transmitter) when polarization matters.
 
== FM radio ==
 
The term "circular polarization" is often used erroneously to describe mixed polarity signals used mostly in [[FM radio]] (87.5 to 108.0 MHz), where a vertical and a horizontal component are propagated simultaneously by a single or a combined array.
This has the effect of producing greater penetration into buildings and difficult reception areas than a signal with just one plane of polarization.
==Mathematical description of circular polarization==
 
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== FM radio ==
 
The term "circular polarization" is often used erroneously to describe mixed polarity signals used mostly in [[FM radio]] (87.5 to 108.0 MHz), where a vertical and a horizontal component are propagated simultaneously by a single or a combined array.
This has the effect of producing greater penetration into buildings and difficult reception areas than a signal with just one plane of polarization.
 
[[Category:Polarization]]