Optimization of S-parameters of microstrip patch antenna in CST

[sas11]

Hello cst designers!

I've designed a poor microstrip p_atch antenna, and I need to optimize the |S(1,1)| dB.
I need to find the minimum level that the |S(1,1)| dB can be reached, but when I use the "min"operator in the optimizer,it means: "The optimizer tries to minimize the S-parameter data. Minimizing the S-parameter data means that the optimizer tries to find a parameter setting where the maximum of the S-parameters over the given frequency range is as low as possible."And as I said before ,I need to find a parameter setting where the minimum of the S-parameters over the given frequency range is as low as possible.
Any suggestions?
regards...

 

[mogwai]

cst optimizer

To minimize the overall S11 min value, you'll need to add a User Defined Goal... In online help you can find this example:

Global minimum:

Option Explicit 
Function GoalFunction() As Double 
  Dim s11 As Object
  Set s11 = Result1D("d1(1)1(1)")
  'Minimize S11
          GoalFunction = s11.GetY(s11.GetGlobalMinimum()) 
End Function

which takes the Global Minimum value of S11 and assigns this value to the goalfunction (to be minimized).

mogwai.

 

[yuen_cityu]

cst frequency range setting

Maybe try to use "move min" operator and set the "Frequency" to be your expected frequency

 

[u_f_o]

optimizing a user defined goal in cst

dear sas11 !

I've designed a poor microstrip p_atch antenna, and I need to optimize the |S(1,1)| dB.
I need to find the minimum level that the |S(1,1)| dB can be reached, but when I use the "min"operator in the optimizer,it means: "The optimizer tries to minimize the S-parameter data. Minimizing the S-parameter data means that the optimizer tries to find a parameter setting where the maximum of the S-parameters over the given frequency range is as low as possible."And as I said before ,I need to find a parameter setting where the minimum of the S-parameters over the given frequency range is as low as possible.

please try think once more: what do you need?
btw s11 in frequency range has several minima and several maxima. some minimum is lowest and some maximum is greatest.
1. you said you need lowest minimum to be as low as possible. and let all maxima grows?
2. cst optimizer suggest to minimize greatest maximum (to be as low as possible, we say 0.001). it is clearly that all other minima and other maxima will be lower than greatest maximum!

i think you should agree with cst-optimizer suggestion. this is MINIMAX optimization method. you have to learn more on optimization theory.

best regards.
u_f_o

 

[effat]

Re: cst -optimization

Hi,
how can I define a 'user defined goal' for the axial ratio?
Can someone help me with the code for it?
I need to optimize the design parameters to achieve an axial ratio below 3-dB.

Thank you