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I want to know more about radial stub

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g86

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radial stub

1. Where should we use them (Uses)
2. Formulae used to dedign
3. Merits / demerits
4. Numerical modelling
5. Specific problem you faced

:!: :idea: :?:
 

harrysmith

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butterfly stub

The models are implemented in practically every simulation software.
I usually proceed the following way. For example a radial stub to substitute a open stub in the bias network of an amplifier. I design the square stub and then it its a starting point for optimization.
 

flatulent

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stub radiale

These have the same properties as a quarter wave uniform width line only they have them over a wider bandwidth.

So the tradeoff on deciding to use them is the board area taken up and the need for a short over a wider frequency range.

Since you like to experiment, here is a utility program for stubs you can play with.
 

g86

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radial quarter wave stub

Thanks a lot for the program. BTW do you have the formulae?

:!: :idea: :?:


flatulent said:
These have the same properties as a quarter wave uniform width line only they have them over a wider bandwidth.

So the tradeoff on deciding to use them is the board area taken up and the need for a short over a wider frequency range.

Since you like to experiment, here is a utility program for stubs you can play with.
 

g86

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radial stub model

I just want to add another query.

Can we use triangular stubs instade of radial one becaus trangular stubs are easier to optimize. What will I loose?

:!: :idea: :?:
 

flatulent

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amplifier radial stub

The radial stub comes from the radial transmission line investigations around 1940. It might be worh trying the triange to see what degrades. I suspect that the input impedance of a quarter wave stub will be finite and not infinite.
 

gecky

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Hi,

what's the difference between radial stubs and butterfly stub?
Butterfly stub = 2 X radial stub?

It's known that radius of radial stub is around 1/4 wavelength. What about the butterfly?

Thanks!
 

gecky

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Thanks Max!

The formula is real complex..... I'll find the stub length by tuning :)

When is it necessary to put a cap at the end of the 1/4wave line?

Also, it is known that the 1/4wave + radial stub arrangement suppresses even harmonics. How much suppression are we looking at here? Working at f0=6GHz (& without a cap), I got suppression of at 10.5GHz instead of 12GHz. Is this suppose to be the case?
 

max232

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use the software of flatulent or CAD (MWO...) , I did not work on the radial stub .

Regards
 

mycw

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Hi,

I'm also interested on butterfly radial stub, when should we use it? What is its difference comparing to single radial stub? I searched on some webpages but most of them are just deriving the equations...

PS.: I clicked on the link mentioned by max ( https://www.edaboard.com/viewtopic.ph...147&highlight= ) expecting it is the explanation for butterfly stub but it turned out to be an invalid webpage.

Thanks,
Mario Young
 

gata_peter

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Well people....
The sad thing is that the formula is not simple at all!!, but the good one is that I 'm leaving here a pdf where you'll find it. Hope it helps you anyway :cool:.
 

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