Learning Forum

[sghose]

Hi there,

Good day. I am a PhD student at North Carolina A&T State University. I am doing my research on antenna design using magnetic material in HFSS. I have designed a patch antenna using magnetic material at 5 GHz and now I want to give an RF AC signal and do a transient simulation in HFSS but it's giving me an error! So, is it possible to do both time and frequency domain simulation in HFSS?

 

Please help me.

[Jason.k]

Hello Sghose, 

Thank you for reaching out to Ansys Learning Forum. 

Indeed, it is possible to do Transient Analysis and of course Frequency Domain Simulations using Ansys HFSS. 

Hidden in the documentation you may find the answer regarding Transient Analysis & The requirements that the materials need to meet for this type of Analysis.

To be more specific, Materials for transient solutions must meet these requirements:

• Materials cannot have arbitrary frequency dependence in a time-domain analysis. For lossy dielectrics, a Debye model is applied to ensure that the loss remain physical across the spectrum. For lossy metals, a Padé approximation is used for the same reason.
• When lossy materials touch a port, the port solver will launch an excitation that fits the lossless case. This is inherent to most time-domain solvers. The 3D part of the simulation will take losses into account correctly.
• Spatially dependent material properties can be specified through user-defined variables in HFSS. Spatially dependent materials are usually applied for modeling dielectric lens, dielectric waveguides, substrates with graded doping profiles, and graded-index fibers.

More information can be drawn by looking into HFSS Help documentation>HFSS Transient. 

I hope this helps! 😄

Have a nice rest of the day, 
Kind regards, 
Jason. 

[sghose]

Hello Jason,

Thanks for your reply. I have gone through the pdf of "HFSS Transient". I am working on YIG (Yttrium Iron Garnet) which is a magnetic material that is not a diagonal anisotropic material, I guess. 

 

 

1) When I selected "Transient Simulation" from the solution type and then it automatically removed the "Magnetic Biasing" from the "Excitation" tab. And I wanna do it in presence of frequency domain at the same time for 5 GHz.

 

So, is there any other way to do both frequency and time domain analysis at a time? Or, do I need to use another time domain software like CST for that?

 

Any suggestion would be appreciated.

[sghose]

Hello Jason,

Can you atleast tell me how can I design magnetic material like YIG(Yittrium Iron Garnet) using HFSS please?

[Jason.k]

Hello Sghose, 

When you select "Transient Simulation" as the solution type in HFSS, it is designed to affect the available options for the setup, including the Excitation tab.

The Transient solution type has specific requirements and settings that may not be compatible with "Magnetic Biasing." This is why you might have noticed that "Magnetic Biasing" was automatically removed from the "Excitation" tab upon selecting "Transient Simulation." 

As we can see from the error, such material is not supported with the specified solution type in HFSS. Since that HFSS Transient solver has specific capabilities, this might require further assistance or coupling with other Ansys Software. Also, since we are referring to a complex -non straighforward- problem, for this type of issues, please, feel free to contact us through Ansys Technical Support by raising a Case. 

Regarding on how to design magnetic material using HFSS: This procedure involves specifying material characteristics for your structure. According to the Ansys HFSS documentation, when creating a ferrite material, you need to define the net internal field that biases the ferrite by assigning a magnetic bias source. This bias field aligns the magnetic dipoles in the ferrite, producing a non-zero magnetic moment. You can select the 3D ferrite object to which you want to assign the magnetic bias source and specify whether the applied bias field is uniform or non-uniform. For more detailed info please, refer to our documentation and search for "Assigning Magnetic Bias Sources"

As mentioned previously, please, do not hesitate to contact Ansys Technical Support for this type of problems in case you need further & detailed assistance.

Kind regards, 
Jason.