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HFSS Transformer simulation problem

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tompson

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hfss out of memory

I am trying to model a transformer using two spiral inductors on two separate chips. This setup is commonly used for magnetic resonance coupling to send data between two substrates. I want to eventually export the results into a spice simulation; however, I am getting some execution errors when I try to simulate the setup.

I get:

[info] Simulation completed with execution error on server: Local Machine. (2:42 PM Mar 22, 2007)
[error] Initial mesh, process mesh3d : Unable to recover all the surface triangles. Additional information may be available in the "model_analysis.html" file in the project results directory.

Now, I imagine you would usually get this due to not enough mesh points or even due to discontinuities on surfaces that are supposed to be united or touching, however I cannot find any such problems with my model.

A note: The reason why I am using inductors of so many turns is because Q is not important in the coupled resonators. The magnitude of L is most important since you need adequate coupling between the two inductors. Furthermore, since the data is typically sent by inducing short current pulses in a positive or negative direction across the tx inductor, high Q inductors are prone to oscillatory behavior.

Can some one please help me out here!!
 

Ruritania

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transformer simulation

Hi, tompson,

Don't worry, "[error] Initial mesh, process mesh3d : Unable to recover all the surface triangles." might be caused by the large ratio between the layers' length/width and thickness. If you have very thin layers, please merge it into other layers. In simulation, the simpler substrate definition, the better.

Hope this helps,

Ruri
 

tompson

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out of memory hfss

so, you're saying the substrate dimensions are wrong?
 

Ruritania

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ads transformer hfss

Hi, tompsom,

I did not download your hfss project before, therefore I only guessed that you might have the thin layer problem.

Now I've downloaded your project, I do not quite understand your project ... I'm just curious, does the transformer structure in your HFSS project extractly like the one in reality? Since I found in your project everything is doubled: two substrates,two oxides, two ground ....

Construct structure exactly the same with the one you will make measurement is extremely important for all EM modelings.

Good luck,

Ruri
 

leander

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transformer hfss

tompson,

To my experience, HFSS cannot solve such a complex structure. Even if it can succeed in the initial mesh, It cannot reach the accuracy in the adaptive passes.

I have tried a much simpler structure (also a transformer) and HFSS resulted in "out of memory". My computer has 2GB memory, which is the maximum that HFSS can deal with, at least for version 9.2.

Best regard,
Leander
 

tompson

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hfss tramsformer

it is. I will also be testing structures with fewer turns and different dimensions. I have the fewer turn models working fine in HFSS. 10 turns is ok, but 12 does not. I'm guessing the adaptive meshing algorithm cannot deal with such a complex structure.

As I have mentioned, high Q and frequency responce characteristics are not imporant for this project.

The reason why everything is doubled is because I drew the base substrate first and then mirrored the model to save on construction time. I have actually written a matlab script that generates the entire structure from scratch depending upon dimensions you give it. There is also a script for inductors which I have also added. See attachment. Feel free to try it out!
 

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