# Z11,Z22,Z12,Z21 on CST MWS

Discussion in 'Wireless & RF Design' started by GIGER, Mar 30, 2015.

1. ### GIGER Thread Starter New Member

Feb 17, 2015
4
0
Greetings!

If anyone is familiar with this program, please let me ask you something.

If I have designed 2 dipoles with 1 port at each one, in 1D results I have in Zmatrix the Z11,Z22,Z12,Z21.
Can you describe what does the program do in order to calculate these results, because i'm really confused.
That'd be a precious help.

Thank you!

2. ### Papabravo Expert

Feb 24, 2006
11,129
2,172
I'm not familiar with that one, but I have used EZNEC. That program uses numerical integration to solve differential equations that have as their solutions, the radiation patterns of antennas as well as their impedance parameters.

3. ### GIGER Thread Starter New Member

Feb 17, 2015
4
0
My basic problem is this:
I have an equation that i can calculate theoritically the Z parameters, but the calculated results with the simulated results are not equal.(not even close)
I think that the program short or open circuit some of the ports in order to do the simulations.
I found (i dont know if its true) that the Z12 on CST means that you have excitation in one of the two ports and the second one is open circuited.
is this true?

4. ### Papabravo Expert

Feb 24, 2006
11,129
2,172
That sounds right, but IIRC the reason we don't use Z parameters is because it requires open and shorted ports. We used s-paramters and the equipment just measured them without going through the gyrations.

Have you tried simulating something simple you know the answer to?

5. ### GIGER Thread Starter New Member

Feb 17, 2015
4
0
Nope... And i haven't found something useful telling about Z matrix and Y matrix.
If you think about a 2 port circuit my previous post maybe its true, but i want someone to confirm this.

Feb 24, 2006
11,129
2,172