The purpose of this blog is to examine the differences between the Optislang optimizer and the AEDT standard optimizer under the same conditions and constraints. A waveguide T-junction W975 was used as an example for the comparison.
The user must download Optislang from the Ansys Customer Portal. It is also necessary for the license file to contain the license for Optislang.
We will begin with the HFSS model. A T-Junction waveguide has been designed, and we are interested in optimizing the dimensions of the transition to minimize return loss.
The T-junction is a power splitter, so the impedance of the main line, say Zo, must be transferred to two parallel arms of the same impedance, Zo. The main Zo is viewing Zo/2. Wide sections of the main line and narrow sections of the side arms perform the transfer function.
The variables are:
AEDT optimizer will be used to optimize the design
Using Quasi Newton Gradient solver:
The variables' ranges are as follows:
The optimizer should be saved and run. The results are as follows:
AEDT optimizer solved 75 models. The optimization took 54 minutes to complete. Twelve cores were used by the computer.
Close AEDT. Optislang can be launched as a standalone application by the user.
Create a new project. Select File, New Project.
Drag the Solver Wizard to the middle of the screen. Choose Ansys EDT, select the file, then select Open.
The Input Tree and the Output Tree should be expanded. (could be called (_shared_). Select all variables in the input panel, right-click, and set them as Parameters. Right-click on the S-parameters in the Outputs panel, and set them to Responses. The final setup is shown below.
Next, modify the ranges. Same numbers used in AEDT.
The objective of the criteria is to minimize the maximum S11 value. Click Objective, a new line will be added in the Criteria panel. The expression will be $SIG_MAX_Y(S_parameters). Select MIN in the Criterion column.
You can add variables, constraints (certain relationships between design parameters), and limit states. A new row is added to the table if you press any of them. Click the Next button.
Finish. A new structure is created in the middle.
Drag and drop the Optimization Wizard. Fill out the forms as needed. We select to use the OCO optimization.
And you get this:
Right click on the One-Click Optimization banner and select Start from here. Take the numbers obtained from Optislang, and run a new HFSS model using them.
The simulation lasted 2:50 hours, with 192 trials. The results are better than -24.2243dB. Although it took longer time, the final result is way better than the optimizer used in Ansys AEDT (-14.5dB).
