March 13th 10, 03:57 PM
posted to rec.radio.amateur.antenna
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external usenet poster
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First recorded activity by RadioBanter: Mar 2008
Posts: 1,339
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Parallel tank circuit
On Mar 13, 6:23*am, Richard Fry wrote:
On Mar 12, 8:08*pm, Art Unwin wrote:
... Planar designs are usually
designed upon a single polarity and not so much as supplying
sensitivity to other polarities, where as designs based upon optimiser
versions are made sensitive to all types of polarity such that useable
*incoming signals for communication climbs up several 100 percent.
Art (N.B. please) ...
The POLARITY of an electromagnetic wave is determined by its electric
field vector, which reverses direction (polarity) every 180 degrees of
the waveform -- regardless of the polarization of the wave.
The POLARIZATION of an electromagnetic wave is defined by the physical
orientation of its electric field vector, regardless of the polarity
of that field. For linear radiators such as a dipole and monopole, the
direction of polarization is that of the physical orientation of the
radiator.
So although these terms rather sound the same, they aren't synonymous.
The applet linked below is useful to visualize this. To see vertical
polarization, first set the Ey field to zero, and start the animation
(top center of the page). Then set the Ex field to zero and the Ey
field to one to see horizontal polarization. *The blue lines tending
to fill in the a-c waveform represent the field vectors of the
radiated wave.
In this applet if the Ex and Ey fields are set to equal values (say at
1 each), and their phase relationship to -90 degrees using the slider
below the Ex and Ey sliders in the Input Section of the applet, then
the resulting e-m field is perfect, right-hand circular polarization.
The animation shows a net field vector of constant magnitude rotating
through all polarization angles once per wavelength.
Also note that the perfect, c-pol field shown in the applet is the net
field of two, linearly-polarized radiators when configured as
described above.
http://www.amanogawa.com/archive/Pol...zation2-2.html
RF
Thank you for the heads up
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