Designer’s Guide Community

Yutao Liu

Community Member

Offline

Posts: 76
Guangzhou, China

A few questions about inductors simulation with HFSS
Feb 26^th, 2009, 7:36pm

hello everybody,

I want to model and to analyze inductors with HFSS. I found that the poly layer was not added when I read some examples. Why? Is the simulation more accurate after adding the poly layer?

And is it appropriate to only add those shield metal layers under the inductor,when I want to simulate the floating shield inductor which is some metal layers are added underneath the inductor? Is there anything else I should set up due to the shield metal layers?

thanks!

Back to top

IP Logged

pancho_hideboo

Senior Fellow

Offline

Posts: 1424
Real Homeless

Re: A few questions about inductors simulation with HFSS
Reply #1 - Feb 27^th, 2009, 7:31pm

Yutao Liu wrote on Feb 26^th, 2009, 7:36pm:

I want to model and to analyze inductors with HFSS.
I found that the poly layer was not added when I read some examples. Why?
Is the simulation more accurate after adding the poly layer?

I can't understand a meaning of your question.

Is Poly Layer used in your inductor structure ?
Just Poly Layer isn't used in inductors of examples you saw, is it ?

Yutao Liu wrote on Feb 26^th, 2009, 7:36pm:

And is it appropriate to only add those shield metal layers under the inductor,when I want to simulate the floating shield inductor which is some metal layers are added underneath the inductor?

I can't understand a meaning of your question.

What do you refer as "those" ?
Is there any relation with Poly Layer ?
If your process have only two metal and one poly, you have to use poly layer as shield layer.

Yutao Liu wrote on Feb 26^th, 2009, 7:36pm:

Is there anything else I should set up due to the shield metal layers?

No one except for you knows process profile(layer profile) you use.

This is also true for your another question. No one except for you knows your specific situations.
http://www.designers-guide.org/Forum/YaBB.pl?num=1231747377/0#0

Back to top

Kita━━━━━━(ﾟ∀ﾟ)━━━━━━ !!!!!
http://www7.plala.or.jp/ungeromeppa/flash/kita.html
http://www.youtube.com/watch?v=mjIxGh55bMM&feature=related

IP Logged

Yutao Liu

Community Member

Offline

Posts: 76
Guangzhou, China

Re: A few questions about inductors simulation with HFSS
Reply #2 - Mar 1^st, 2009, 7:04pm

Thanks for pancho_hideboo's replying!

I am new with HFSS, so i don't quite understand the settings such as boundarier and terminals in HFSS.

pancho_hideboo wrote on Feb 27^th, 2009, 7:31pm:

Is Poly Layer used in your inductor structure ?
Just Poly Layer isn't used in inductors of examples you saw, is it ?

Yes, poly layer was not used in inductors of the example I mentioned. �So, the poly layer should be omitted in the model due to its absence in the inductor structure?

pancho_hideboo wrote on Feb 27^th, 2009, 7:31pm:

What do you refer as "those" ?
Is there any relation with Poly Layer ?
If your process have only two metal and one poly, you have to use poly layer as shield layer.

There are 1 poly layer and 6 metal layers in the process i use, and i use the metals as floating shield layers rather than the poly.

I actually want to know whether HFSS would take the shield layers into account when analyzing when these shield layers is "floating", that is, they aren't connected to any terminals or "ground" and they are not connected to the spiral inductor.

Furthermore, the floating shield layers are used to limit the effect from eddy current formed in the substrate. Can HFSS take the eddy current into account during calculation by default? If it can't, how should i do?

Back to top

IP Logged

pancho_hideboo

Senior Fellow

Offline

Posts: 1424
Real Homeless

Re: A few questions about inductors simulation with HFSS
Reply #3 - Mar 2^nd, 2009, 5:42am

Yutao Liu wrote on Mar 1^st, 2009, 7:04pm:

I am new with HFSS, so i don't quite understand the settings such as boundarier and terminals in HFSS.

If you want someone to understand your questions, you have to describe your questions regarding situation and condition in detail using industrial standard terminologies.

Yutao Liu wrote on Mar 1^st, 2009, 7:04pm:

Yes, poly layer was not used in inductors of the example I mentioned. �
So, the poly layer should be omitted in the model due to its absence in the inductor structure?

If you don't include objects made by poly layer inside your analysis area, poly layer is naturally unused.

Yutao Liu wrote on Mar 1^st, 2009, 7:04pm:

I actually want to know whether HFSS would take the shield layers into account when analyzing when these shield layers is "floating", that is, they aren't connected to any terminals or "ground" and they are not connected to the spiral inductor.

Of course, Ansoft HFSS can taka such effects into account since it is Full-Wave Analysis by FEM.

Yutao Liu wrote on Mar 1^st, 2009, 7:04pm:

Can HFSS take the eddy current into account during calculation by default?

Of course, Ansoft HFSS can taka such effects into account since it is Full-Wave Analysis by FEM.

I can't understand why you are confusing.
There is no special problem at all in your situation.

Back to top

« Last Edit: Mar 2^nd, 2009, 6:44am by pancho_hideboo »

Kita━━━━━━(ﾟ∀ﾟ)━━━━━━ !!!!!
http://www7.plala.or.jp/ungeromeppa/flash/kita.html
http://www.youtube.com/watch?v=mjIxGh55bMM&feature=related

IP Logged

Yutao Liu

Community Member

Offline

Posts: 76
Guangzhou, China

Re: A few questions about inductors simulation with HFSS
Reply #4 - Mar 4^th, 2009, 4:40am

pancho_hideboo wrote on Mar 2^nd, 2009, 5:42am:

Yutao Liu wrote on Mar 1^st, 2009, 7:04pm:

Can HFSS take the eddy current into account during calculation by default?

Of course, Ansoft HFSS can taka such effects into account since it is Full-Wave Analysis by FEM.

I can't understand why you are confusing.
There is no special problem at all in your situation.

I am confusing because I am not sure which types of boundaries I should assign.
Should I draw a new rectangle covering the bottom face of substrate and assign it as "Perfect E" boundary?
I doubt about this assignment because I want to model a lossy substrate.

Back to top

IP Logged

pancho_hideboo

Senior Fellow

Offline

Posts: 1424
Real Homeless

Re: A few questions about inductors simulation with HFSS
Reply #5 - Mar 4^th, 2009, 4:53am

Yutao Liu wrote on Mar 4^th, 2009, 4:40am:

Should I draw a new rectangle covering the bottom face of substrate and assign it as "Perfect E" boundary?

No. If you use perfect electrical wall boundary, it must be far from substrate, here an area between substrate and perfect electrical wall is air.
You can also use perfect magnetic wall.
If your substrate thickness is enough large, you might be able to omit air.

Also you can set radiation, absorption, periodically boundary conditions.

Mathematically these boundary conditions are well-known
Dirichlet boundary condition, Neumann boundary condition, Mixed boundary condition, Sommerfeld radiation condition, etc...

You should read text book about electric magnetic theory and then manuals of Ansoft HFSS.

Back to top

« Last Edit: Mar 4^th, 2009, 7:39am by pancho_hideboo »

Kita━━━━━━(ﾟ∀ﾟ)━━━━━━ !!!!!
http://www7.plala.or.jp/ungeromeppa/flash/kita.html
http://www.youtube.com/watch?v=mjIxGh55bMM&feature=related

IP Logged

Yutao Liu

Community Member

Offline

Posts: 76
Guangzhou, China

Re: A few questions about inductors simulation with HFSS
Reply #6 - Mar 5^th, 2009, 4:17am

pancho_hideboo wrote on Mar 4^th, 2009, 4:53am:

You should read text book about electric magnetic theory and then manuals of Ansoft HFSS.

I'm a student for analog/RF circuit design, so I am not quite familiar with microwave design, especially modeling passive component in HFSS.
I just want the equivalent circuit of a floating shielded inductor to do my circuit design.
Is there any other better ways to achieve my goal?
Or, which text books about electric magnetic theory is suitable to me?

Back to top

IP Logged