In this blog, we go through the steps for using Ansys Electronics Desktop (AEDT) HFSS together with the OptiSLang-Stochos optimizer to design custom waveguide structures. Stochos, also known as Physics-Informed Bayesian Optimization (PI-BO), is integrated into AEDT through OptiSLang. Unlike traditional optimizers, PI-BO represents a new generation of AI-driven optimization algorithms that combine probabilistic learning with physics awareness. Both OptiSLang and Stochos are third-party tools that operate alongside AEDT, not natively within it.
Model Description
The target design is a non-uniform waveguide T-junction power divider. A standard T-junction equally splits the input signal into two output ports. In this case, the goal is an unequal split, where one output port carries two-thirds of the total power.
Let:
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Power21 = power delivered to Port 2 = |S(2,1)|²
-
Power31 = power delivered to Port 3 = |S(3,1)|²
The optimization objective is therefore:
Power31 – 2 × Power21 = 0
The model is shown below. Since the waveguide height does not significantly affect the field distribution, it was reduced by 80 %, which allows each HFSS solution to complete in less than 15 seconds.
Design Variables
The geometry has four design variables:
| Variable | Description |
|---|---|
| Depth | Groove length in the x-direction |
| Offset | Lateral shift of the groove center |
| Width1 | Extension toward Port 2 |
| Width2 | Extension toward Port 3 |
Each variable’s range is defined in the optimization setup table.
Optimization Procedure
Step 1— Create the groove geometry
Create the groove feature using the four parameters listed above.
Step 2 — Activate design variables
In the project tree, select the model name → double-click “Design Properties” → open the Optimization panel.
Activate all four variables and enter their respective ranges.
4 variables, and enter the extents.
Step 3 — Define output variables
Right-click Results > Output Variables, then add:
-
Power21 = (mag(S(2,1)))^2 -
Power31 = (mag(S(3,1)))^2
Step 4 — Set the optimization goal
Right-click Optimetrics > Add > OptiSLang Setup.
In the Calculations panel, under Setup Calculations, enter the target expression:Power31 – 2*Power21
Then click Add, OK, and confirm.
Step 5 — Create the OptiSLang project
Right-click Optimetrics > Create optiSlang Project
Step 6 — Launch OptiSLang and run Stochos
Right-click the optimetrics > Go to optiSlang. Do not try to solve inside AEDT.
Inside OptiSLang, launch the optimization run using Stochos (PI-BO).
Step 7 — Post-process results
After the solution completes, insert a Post-Processing node from the right-side toolbar and connect it to the main project.
.
Double-click the node to open the results dashboard.
Stochos converged to the optimal design after 44 evaluations.
On the right-hand panel, you can also access additional analysis windows — simply drag any desired view into the main workspace for further visualization.
