Coaxial Resonator Eigenmode Analysis in HFSS

Hello everyone, this is Aded from Ozen Engineering, and in this video, I will show you how to use the Eigenmode solver in HFSS. So, we'll compute the frequency and Q factor of this imported coaxial resonator. First, ensure that you are selecting the right solution type.

So, go to HFSS, solution type, and select Eigenmode. As you can see, the model is currently set to vacuum, so I'll start by assigning a finite conductivity boundary to define the cavity walls as silver. So, I'll select the model, right-click, go to Assign Boundary, and click Finite Conductivity.

Here, I'll change the conductivity to 6.1e7 and click OK. Now, in the project manager, under boundaries, we can find our finite conductivity boundary. The Eigenmode solver does not require any defined sources; you specify the number of modes to compute and the convergence criteria.

So, let's add solution setup, right-click on HFSS, and click Add Solution Setup. Here, I set the minimum frequency to 1 GHz, and we will calculate only the first mode.

I change the maximum number of passes to 20 and the maximum delta frequency per pass to 0. And in the Adaptive Options tab, I'll change the minimum coverage passes to 2. To ensure maximum accuracy, we will change the initial mesh settings.

So, let's go to Mesh, right-click on it, and select Initial Mesh Settings. Here, we will apply Curved Linear Meshing and increase the resolution. Now, we can run a validation check and run the simulation by clicking Analyze All.

Once the solution is complete, the results can be accessed by right-clicking on Setup1, Eigenmode Data, and here you can see the real and imaginary parts of the frequency and the Q factor. The results can also be displayed in a tabular report.

Here, I'll create some output variables first, so right-click on Results, and go to Output Variables. The first variable is the frequency in GHz; we call it mode 1 f for frequency, and the second variable is Q; I will call it mode 1 Q. Here, I'll click Add and Done.

Now, right-click on Results, go to Create, Eigenmode Parameters Report, and select Data Table. Here, we'll select Output Variables and select both Frequency and Q and click New Report. Here, we can see in this table the frequency and Q factor.

Let's also plot the frequency and Q values for each solution pass up to convergence. So, right-click on results, create Eigenmode parameters report, rectangle plot. Here, we change the solution to adaptive pass, and select output variables, select F and Q, and click New Report.

Let's put Q on a different Y, so select Q, go to Y, and select Y 2. Let's also make some field plots on the cross. So, expand Planes and select the YZ plane. Right-click, Go to Plot Fields, E, Mag E, and click Done, and here's our electric field.

To plot the magnetic field, we do the same, select the YZ plane, right-click, go to plot fields, H, Mag H, and click that. Here, I'll hide the electric field, so right-click on Mag E and uncheck plot visibility. And here's our magnetic field. Now, let's hide it and plot the mesh on the YZ plane.

So, I'll select it, right-click, and click Plot Mesh. Here, I'll click Done. And here you can see the mesh on the YZ plane. In this video, we saw how to use the Eigenmode solver in HFSS to compute the frequency and Q factor of coaxial resonators. Thanks for watching, and see you in the next video.

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