Re: A quick lashup 2.3 to 3.4 GHz horn


Alan Beard
 

Hi Kent and all,

On looking at the table in my previous email, I've rebuilt the feed.
The waveguide here is 100 x 50mm OD or 47 x 97mm ID.
So I went for a 20mm wide ridge (start) and because I can't fold a curve,
I elected to widen the ridge as we move away from the feed point.

2300.1  and 3398.1 MHz are my targets.

RF measurement with the NanoVNA V2_2 SAAV2 is very difficult without
good adapters and a good low return-loss terminator in BNC. 

(So many of the BNC terminators here are from "Thin-Net" 10Mbits)

I find BNC hardware so practical.

Anyway, the horn is ready for service.

Alan VK2ZIW

On Sun, 6 Jun 2021 13:53:32 +0000 (UTC), KENT BRITAIN wrote
> Hi Alan
>
> Most of these horns are used on my antenna range and have Network Analyzer S11 and Gain tables laminated on them.   Yes, they work nicely in 50 Ohm systems.
>
> Traditionally on an exponentiation Slot or Vivaldi antenna the feed point was 1/4 wave in front of a short.
> Later is was learned that replacing the 1/4 wave slot with a circle greatly broadened the frequency response of the antenna.      As for the ridges themselves.   The size of the opening determines the lowest frequency they will work at. How close you can position the slots determines the highest frequency.   Basically it's the structure behind the feedpoint that is helping to set the impedance.
>
> Kent
>
> PS  I like to think to the Vivaldi antennas as a ridged horn without the horn! hihi
>
> On Sunday, June 6, 2021, 04:32:47 AM CDT, Alan Beard <beardal@...> wrote:
>
> Thanks Kent,
>



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Alan VK2ZIW
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