[amsat-bb] Patch antennas

[BobsImsai8800@xxxxxxx]

>From K5GNA:

I have been looking at using standard G-10 expoxy boards to build a true 
circularly polarized patch antenna.  Most of the designs out there are really 
linear polarization.   The copper can be etched with the shape and precision 
required for a true CP design  on the copper, but with the glass epoxy 
dielectric, it wouldn't be practical to use with its built in backplane on 
double sided board.

But, by turning the copper toward a separate backplane and using air 
dielectric, it would be feasable.  The PC board is out of the area affected 
by the dielectric.  The excess bare board around the copper could be used for 
supports that are out of the affected area. If you used an oversized circular 
PC  board, it  could be used as a plug for a cylinder to make it weatherproof.

Does anyone have any good designs for a true CP patch with air dielectric?
TNX,

Bob Seydler
K5GNA  
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