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Re: Patch plans anyone?



Actually, it would be interesting to see how well a PCB etched patch would 
do on a good, low-dielectric, substrate as it could be a inexpensive way to 
make a decent feed that is VERY reproducable.

The conventional logic so far is that we want the air dielectric to get the 
aperature area of the patch to be maximum.  This gives maximum gain.  But, 
as long as the dish illumination is good, the gain of the feed isn't really 
that important, the pattern is.

Does going to teflon (Er=2.1), shrinking the patch 2x, make that much 
difference in the pattern?  Or just the gain?  Has anyone been able to model 
this?  One other potential problem is that the bandwidth of the patches 
generally decreases with narrower substrate.

If anyone makes progress on this, please let us know.

Fred W0FMS

>From: Mike73@aol.com
>To: howard@howardlong.com, amsat-bb@AMSAT.Org
>Subject: Re: [amsat-bb] Patch plans anyone?
>Date: Thu, 30 May 2002 13:02:05 EDT
>
>In a message dated 5/30/02 11:58:26 AM Eastern Daylight Time,
>howard@howardlong.com writes:
>
> > Does anyone have any plans for a patch antenna made on PC Board?
> >
> >  I would guess that the PC Board will have to be a particular type.
> >
> >  My intention is to try stacking a number of them on a single board as 
>an
> >  experiment, so RHCP would be nice.
>
>Howard,
>
>There was a two part article in VHF Communications Q1 and Q2 2001 titled
>"Modern Patch Antenna Design" by DG8GB. I haven't read it all yet, but the
>articles focus on building a patch for Meteosat (1691 MHz) using Rogers
>RT-Duroid RO4003 material.
>
>The articles used "Pcaad21" and "patch16" for design. Both available on the
>web. The author found the numbers generated in "patch16" to be closer to
>measured values. "PUFF" was used for matching sections.
>
>Good stuff so far. Now to find time to finish the articles.... Hope this
>helps!
>
>73,
>Mike, N1JEZ
>AMSAT #29649
>Local Area Coordinator
>"A closed mouth gathers no feet."
>----
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