Videos > Using Expression Input in HFSS and Maxwell's Fields Calculator
Jun 28, 2025

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Using Expression Input in HFSS and Maxwell's Fields Calculator

Hello everyone, this is Adel from Ozen Engineering. In this tutorial, I'll demonstrate how to enable support for expression input in the Fields Calculator for HFSS and Maxwell. This feature is available in beta in the 25 R1 release.

Enabling the Feature

  1. Go to Tools > Options > General Options.
  2. Under General, select Desktop Configuration and click Beta Options.
  3. Enable the feature for HFSS. Scroll down to find the same option for Maxwell and enable it.
  4. Click OK and restart the application to apply the changes.

Calculating Capacitance

With the feature enabled, let's calculate the capacitance of the spiral plate. I have already run the simulation, and the capacitance is 14.941 pF.

Capacitance Formula

The formula for capacitance is:

  • ε0 × εr × Area of the plates / Distance between the plates

I have created a 2D object named A for calculating the area.

Using the Fields Calculator

To open the calculator:

  1. Right-click on Field Overlays and select Calculator.

Stack Method

  1. Add a named expression for the area by integrating 1 over the surface:
    • Go to Number, enter 1.
    • Go to Geometry, select Surface, and choose A.
    • Click OK and then Integrate.
    • Click Add and name it A.
  2. Enter the capacitance formula:
    • Multiply ε0 and εr.
    • Copy A to the stack and click Multiply.
    • Divide everything by the distance d.
  3. Click Evaluate to see the capacitance is 14 pF.

Algebraic Method

  1. Enter ε0 and multiply it by εr and the area A.
  2. Integrate 1 over the surface:
    • Go to Geometry, click Surface, and select A.
  3. Divide by D and click Evaluate to get the result of 14.941 pF.

Switching between the two methods will convert the expression accordingly.

Conclusion

In this video, we demonstrated how to enable support for expression input in the Fields Calculator. Thank you for watching, and see you in the next video.

For more information, please contact us at Ozen Engineering, Inc.

[This was auto-generated. There may be mispellings.]

Hello everyone, this is Adel from Ozen Engineering. In the studio, I'll show you how to enable support for expression input in the Fields Calculator for HFSS and Maxwell. This feature is in beta in the 25 R1 release.

In this example, we will calculate the capacitance using both stack and algebraic methods. To enable the feature, go to Tools > Options > General Options. Under General, select Desktop Configuration and click Beta Options.

Here, we can enable it for HFSS, and if I scroll down, we have the same option for Maxwell, and click OK. And now we need to restart the application to apply the changes, so I click yes. With this feature enabled, let's now calculate the capacitance of the spiral plate.

I have already run the simulation, so if I right-click on Results, and click Solution Data, we can see that the capacitance is 14.941 pF. Now let's use the calculator to confirm this result. Just before I open the calculator, a quick reminder of the capacitance formula.

So we have epsilon naught multiplied by epsilon r multiplied by the area of the plates divided by the distance between the plates. Here, I have created a 2D object named A, which I will use to calculate the area.

Now let's open the calculator by right-clicking on Field Overlays and selecting Calculator. Now we have the two options, Stack and Algebraic. I start with the stack method and begin by adding a named expression for the area, which is calculated by integrating 1 over the surface.

So here, let's go to Number, enter 1, then I go to Geometry, I select Surface, and I'll select A, click OK, then integrate. Now to add the named expression, click Add, and I'll name it A. Now let's enter the capacitance formula. So I'll multiply epsilon naught and epsilon r.

Then let's copy A to the stack and click multiply. And we'll divide everything by the distance d. So select d and then divide. Now let's click Evaluate, and as you can see, the capacitance is 14 pF. Now let's switch to the algebraic method, which is straightforward.

So here, I enter epsilon naught and I multiply it by epsilon r and I multiply it by the area A. So here, I will integrate 1 over the surface. So I'll go to Geometry, click Surface, and select A. And then I'll divide this by D. So here, if I click Evaluate, again the result is 14.941 pF.

Also, when you switch between the two methods, the expression is converted accordingly. In this video, we saw how to enable support for expression input in the Fields Calculator. Thanks for watching, and see you in the next video.

Please contact us at https://ozeninc.com/contact for more information.

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