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calculation of input impedance in CST

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kamiar.t

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hello everyone

How can I calculate input impedance and radiation resistance in CST while i am using discrete port?

regards
 

in 1D report section CST always calculate input impedance.
when simulation run finished. it will appears in navigation tree.
 
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redcrystalline said:
in 1D report section CST always calculate input impedance.
when simulation run finished. it will appears in navigation tree.
Click to expand...

thanks @redcrystalline for your help

but i have problem with that, when I change the impedance of a discrete port (for example form 50 ohms to 300 ohm) then the input impedance of what CST shows change too !!! i think input impedance should be constant and only S-parameters should be change
 
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I suppose you are wrong.
go to post-processing section and check s-parameter calculation>>always calculate z and y matrices.
then look at z folder in 1d result an navigation tree.
z matrices never change with reference impedance
 

redcrystalline said:
I suppose you are wrong.
go to post-processing section and check s-parameter calculation>>always calculate z and y matrices.
then look at z folder in 1d result an navigation tree.
z matrices never change with reference impedance
Click to expand...

yes I know that but it differ slightly when i change reference impedance from 10K to 35K, but now i have another problem :(
when i saw the real part of input impedance in Z-Matrix i observed that in some frequencies the real part is negative, i can't understand it?
 

kamiar.t said:
yes I know that but it differ slightly when i change reference impedance from 10K to 35K, but now i have another problem :(
when i saw the real part of input impedance in Z-Matrix i observed that in some frequencies the real part is negative, i can't understand it?
Click to expand...

Attach your design. I guess your simulation is wrong.
Negative Resistance mean Active Element and This is impossible because CST Full-wave dose not support active elements.
 

can you please tell me how to attach it, :bang:

it has some selection list for insert picture, video or a link but not any way for attach a file
 

kamiar.t said:
can you please tell me how to attach it, :bang:

it has some selection list for insert picture, video or a link but not any way for attach a file
Click to expand...
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Untitled-1.pngi don't see any negative resistance?
 
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eee.jpg
redcrystalline said:
- - - Updated - - -

View attachment 119278
i don't see any negative resistance?
Click to expand...

I'm highlighting the negative resistance, maybe you do it with finer mesh???
what do you do in a Mix 1DC results in post processing?
or what i should do to give the same result?
 
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if my result is correct then do this:
go to solver setting windows click on special>>choose waveguide tab
then change port mode solver to Generalized and check broadband for inhomogeneous port option
then in solver setting windows check adaptive mesh refinement option.
after all of this you will see my results.
 

redcrystalline said:
if my result is correct then do this:
go to solver setting windows click on special>>choose waveguide tab
then change port mode solver to Generalized and check broadband for inhomogeneous port option
then in solver setting windows check adaptive mesh refinement option.
after all of this you will see my results.
Click to expand...

I'm not sure about your result but it is more correct from me :)
but I didn't use any waveguide port to check broadband for inhomogenous waveguide port , i think it is only for use of waveguide port not discrete port which used in this structure
 

kamiar.t said:
I didn't use any waveguide port to check broadband for inhomogenous waveguide port , i think it is only for use of waveguide port not discrete port which used in this structure
Click to expand...
You're right. my mistake.
By the way what else remain?
 

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