Re: [amsat-bb] Dish

["Edward R. Cole" <al7eb@xxxxxxxxxxxxx>]

>Actually, there are several versions of "flat plate" antenna that have
>existed commercially. ***snip***
>
>Another form of flat antenna simulates a parabolic reflector using
>unterminated dipole elements strategically arranged on a flat plate. T
***snip***
>Just about every Inmarsat terminal shipped these days employs a flat panel
>antenna. These are all patch arrays fed in phase. No feed is required since
>these are not lense antenna's. The majority of Inmarsat antenna's come from
>one manufacturer in South Africa, Omnipless, www.omnipless.com . In my
>experience, a well designed patch array can't be beat for long term
>performance in a transportable environment. On the other hand, it's hard to
>beat the dB/$ ratio of a piece of formed aluminum! Every type of antenna has
>advantages and dis-advantages. It all comes down to applications and what's
>important to YOU.
>
>Howie, AB2S

No arguement that there are several alternative antenna designs to the
"old" parabolic reflector "dish".

I think the original characterization of a "flat dish" was a bit of
oxymoronism in that the only flat dishes I've had were left in the driveway
and the "significant other" ran over them!  They generally didn't perform
up to spec afterwards...;-)

Certainly planar "flat" antenna designs are interesting and may be
desirable from asthetics.  I particularly found the idea of phased patch
antennas an interesting one...especially when considering
portability...satellite rovers take notice!

Commercial ones I've read about have utilized etched pcb construction.  I
wonder about dielectric effects.  Also dual-side board to utilize the
baqckside as a reflector plane.  Maybe four panels sized for carrying in a
breifcase and snap-together for deployment at your destination...having 24
dBi at 2.4G....now that would be real nice! 

Keep on scheming and dreaming!

Ed, AL7EB

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