Re: Calculating the impedance of a dielectric rod in free space to get a match to 377 ohms?


Neil Smith G4DBN
 

Certainly adding a choke ring lets me clean up the sidelobes radically, as does converting the design to a non-lensed Pickett-Potter or W2IMU, but my primary intent was to make a lens horn that can be mounted very close to a 5.6 GHz horn on the same dish, so keeping the outside diameter under 25mm would be good.

I think I've found another paper about characteristic impedance of an unenclosed dielectric guide, although it is densely mathematical, so I need a good night's sleep before reading it. If it makes any sense to me, I'll add a link to it on the UKuG wiki and write a covering page.

Neil

On 11/03/2021 13:22, Mike Willis wrote:
Try a pie tin (aka Chaparral ring) as it will help reduce sidelobes
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