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Re: Patch Antennas



At 03:42 PM 11/6/98 +0000, you wrote:
>The idea of using a patch antenna array is very interesting.  Has anyone tried 
>using one for receiving the digital satellites?
>
>Can anyone give the dimensions for a patch antenna for 435 MHz?
>
>I believe that using a feed point on one of the diagonals will give a circular 
>polarization.  

                                           NO!
>
>
>-- John Melton  n6lyt/g0orx

Hi John,
>
Here is what I wrote ( Anomalous Propagation Newsletter for October 98)
about a presentation at this years "Pack Rats" Conference:

Chris Fagas, WB2VVV, next talked about PATCH Antennas.  These antennas are
used on aircraft, satellites and sometimes on cars.  He also showed a 28 GHz
array which had a gain of 30 dBi.  This type of "flat plate" antenna may be
used by hanging it in a window for direct TV.  The phase 3 d  satellite has
6 round circular polarized patch antennas for 70 CM and more for GPS.  Chris
concentrated on square patches using mainly 62 mil double sided pc board
(5880, e=2.2). The material should be low loss and as could be expected air
insulation is best.  Dimensions Chris gave for the sides of the patches are
432 MHz...9".  903 MHz ...4.35",  1296 MHz ... 3.03",  2304 MHz ... 1.704",
3456 MHz ... 1.136",  5760 MHz ... .682",  and 10 GHz ....379".  The gain
you can expect from one element is around 6.5 dBi. Chris managed to put 5
microwave band patches on a single large circuit board, a nice compact
arrangement for field trips.  Feeding of the patches is off center from the
back plane to get 50 Ohms, and since the patch is square a second feed can
be added to obtain circular polarization.  Naturally, Chris also
experimented with array configurations in order to increase the gain.  More
can be found on his Website: WB2VVV.com


73,  Gerd,  WB8IFM in Dayton.

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