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Old August 14th 07, 01:04 AM posted to rec.radio.amateur.antenna
amdx amdx is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 349
Default Patch antenna Polarization?


"nx7u" wrote in message
oups.com...
Yes to both.
A corner-fed patch is roughly circularly polarized...I say roughly
because there are some other pertubations typically made to force the
sense of the CP, and also to improve the circularity.
But if the feed is just offset a bit (like 1/4-3/4 rather than
1/2-1/2)...well that should act similarly to an offset-fed dipole, so
you'd have higher input impedance and some feedpoint reactance. And
the pattern linearity would be more elliptical (patches typically have
relatively high crosspolar response anyway).


Ok, to make sure I understand;
If I put the feed on the lowerhalf of the patch the antenna would be
vertically polarized?
And, if I put the feed on the left or right half of the patch the antenna
would be horizontally polarized?
Now to complicate things, I see some patches split the difference and put
the feedpoint on the left side of the lowerhalf. What does that do?
Thanks, Mike


My next trick is to put 4 Patch antennas on one plate, I'm looking for the
proper
spacing between Patches. My guide at this point is this site,
http://www.darc.de/distrikte/g/T_ATV...d-Array-GB.pdf
the author puts 4 biquads on one plate with proper phaseing and impedance
matching.
The author uses .8 wavelength vertical and .9 wavelength horizontal
spacing betwen centers.
I'm thinking 1.0 wavelength between centers is correct, but open to some
correction factor
for some (unknown to me) characteristic.
Any help and leads appreciated,
Thanks. Mike