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CST: Dispersion diagram of LH-transmissoin line

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snkhan

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cst dispersion diagram

Hi
I am trying to simulate the structure of the attached paper (Fig. 4). S-parameter simulation is quite well.

Can somebody help me to simulate the band diagram, using CST 2006.

Thanks
 

dispersion

Hi

I know that the dispersion diagram of any structure can be calculated by CST following

The step are explained the steps explained in its support area.

Somebody who has acess to support area can also help me.

Thanks
 
cst dispertion diagram

I have the same problem,i donot know how to cal the dispersion diagram use CST

Added after 1 minutes:

who can help me?...
 

site:www.edaboard.com cst dispersion diagram

After you get the S-parameters, you will need to convert them to Transfer Matrix parameters. For 2-port networks, they are also referred to as the ABCD parameters.

Then, you will have:

[V1; I1] = [A B; C D]*[V2; I2]

1: input port
2: output port

For convertion from S-parameters to ABCD-parameters you can use any microwave book, e.g., Pozar...

You also know that:

[V2;I2] = [V1;I1]*exp(-j*k*d) //assuming exp(j*w*t) time dependence. I think CST is using this time dependence,too

then:

[V1; I1] = [A B; C D]*[V2; I2] = exp(+j*k*d)*[V2;I2]

aha! exp(+j*k*d) are the eigenvalues of your [A B; C D] matrix!

then, calculate them in matlab using 'eig' command, take the natural logarithm by 'log' and divide to complex imaginay 'j'. that yields k*d = K (bloch wave number)

note: you will need to repeat this process for each freq point in your sweep. for a two port system, you will have two eigenvalues, therefore you will have two bloch wave numbers at each frequency. If the system is reciprocal then w(k)=w(-k) (the dispersion diagram will be symmetric)..

as far as i know, there are no built-in functions for calculating these dispersion diagrams... so you will need a little coding of yours. i hope this helps everyone interested.. :)
 
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    amntt

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Re: site:www.edaboard.com cst dispersion diagram

Zottiri Kusuta said:
After you get the S-parameters, you will need to convert them to Transfer Matrix parameters. For 2-port networks, they are also referred to as the ABCD parameters.

Then, you will have:

[V1; I1] = [A B; C D]*[V2; I2]

1: input port
2: output port

For convertion from S-parameters to ABCD-parameters you can use any microwave book, e.g., Pozar...

You also know that:

[V2;I2] = [V1;I1]*exp(-j*k*d) //assuming exp(j*w*t) time dependence. I think CST is using this time dependence,too

then:

[V1; I1] = [A B; C D]*[V2; I2] = exp(+j*k*d)*[V2;I2]

aha! exp(+j*k*d) are the eigenvalues of your [A B; C D] matrix!

then, calculate them in matlab using 'eig' command, take the natural logarithm by 'log' and divide to complex imaginay 'j'. that yields k*d = K (bloch wave number)

note: you will need to repeat this process for each freq point in your sweep. for a two port system, you will have two eigenvalues, therefore you will have two bloch wave numbers at each frequency. If the system is reciprocal then w(k)=w(-k) (the dispersion diagram will be symmetric)..

as far as i know, there are no built-in functions for calculating these dispersion diagrams... so you will need a little coding of yours. i hope this helps everyone interested.. :)
Click to expand...

sorrry in conversion of s parameter to abcd we have z0 in formulas what should we do with that z0 ?
 

can you give us your matlab codes?
 

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