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Encyclopedia > Circular polarization

In electrodynamics, circular polarization of electromagnetic radiation is a polarization such that the tip of the electric field vector, at a fixed point in space, describes a circle as time progresses. The name is derived from this fact. The electric vector, at one point in time, describes a helix along the direction of wave propagation (see the polarization article for pictures). The magnitude of the electric field vector is constant as it rotates. Circular polarization is a limiting case of the more general condition of elliptical polarization. The other special case is the easier-to-understand linear polarization. Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... Electromagnetic radiation can be conceptualized as a self propagating transverse oscillating wave of electric and magnetic fields. ... In electrodynamics, polarization (also spelled polarisation) is a property of waves, such as light and other electromagnetic radiation. ... In physics, an electric field or E-field is an effect produced by an electric charge (or a time-varying magnetic field) that exerts a force on charged objects in the field. ... In electrodynamics, polarization (also spelled polarisation) is a property of waves, such as light and other electromagnetic radiation. ... In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. ...

Circular (and elliptical) polarization is possible because the propagating electric (and magnetic) fields can have two orthogonal components with independent amplitudes and phases (and the same frequency).

A circularly polarized wave may be resolved into two linearly polarized waves, of equal amplitude, in phase quadrature (90 degrees apart) and with their planes of polarization at right angles to each other. In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. ... Phase, from the Greek phasis, meaning appearance, has a number of related meanings in English. ... Quadrature, derived from Latin quadrare, is a term with various meanings: in astronomy, the line tangent to an objects orbit defines the objects quadrature. ...

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. FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity broadcast radio sound. ...

Results from FactBites:

 Circular polarization selective surface made of resonant spirals - Patent 5280298 (2684 words) A circular polarization selective surface as defined claim 3, wherein a number of the spirals are arranged parallel to each other in a single plane and all their central segments are parallel and perpendicular to the plane. A circular polarization selective surface as defined claim 9, wherein a number of the spirals are arranged parallel to each other in a single plane and all their central segments are parallel and perpendicular to the plane. A circular polarization selective surface as defined claim 14, wherein a number of the spirals are arranged parallel to each other in a single plane and all their central segments are parallel and perpendicular to the plane.
 Polarization (330 words) Light is linearly polarized when its E-field component is in a plane. Circular and elliptical polarization occurs when two or more linearly polarized waves add together such that the E-field of the net wave rotates. For elliptically polarized light both the magnitude and the direction of the E-field varies.
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