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How to import antenna model from HFSS to Cadence? (Read 13290 times)

Jack

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How to import antenna model from HFSS to Cadence?
Oct 12^th, 2009, 2:40am

Hi, All,

I am a student in the field of RF circuit design. Now I want add a general standard antenna into my front-end of the receiver to see the match performance between antenna and LNA.

I have checked some references, it seems HFSS cannot simulate the active circuits (am I right?). So I have to export the antenna from HFSS, then import it into Cadence.

I just want add the antenna as a component in cadence like a port.

My question is:
1. How can I export the antenna from HFSS, in which file format, it can match with cadence?

2. If I add the antenna into cadence successfully, how should I build the testbench, because usually we use the port as the input, but if antenna is in the front of LNA, which kind port should be in the front of antenna (should the port with series resistor, like 50ohms)?

3. Compare HFSS with ADS, which one can give the easier solution?

Maybe you can suggest me some website or papers!

If my question is simple or maybe posted befor, please don't mind, actually I have check the posted topics.

Any comments are appreciated!

Thank you in advance!

Jack

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Jack

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Re: How to import antenna model from HFSS to Cadence?
Reply #1 - Oct 12^th, 2009, 6:14am

In HFSS, as I know, I can export the return loss (S11), the impedance, and the antenna gain.

First, is there an component in Cadence can import these 3 parameters (S11, gain, impedance) at the same time to perform the characteristics as an antenna?

Second, antenna just has S11 parameter, it doesn't have S21, S12, and S22, is it enough to just use S11 to represent the performance of return loss and impedance of antenna together? If S11 can perform impedance of antenna, then I just need to import the S11 and gain of the antenna.

Third, assume the antenna component is added into the cadence, how to add the signal source to simulate the antenna with LNA ? Because for LNA, we can use the "port" from cadence analoglib, but if antenna is in front of LNA, which kind port I can use to start the simulation.

Thanks for any comments!

Jack

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pancho_hideboo

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Re: How to import antenna model from HFSS to Cadence?
Reply #2 - Nov 3^rd, 2009, 12:27am

Jack wrote on Oct 12^th, 2009, 2:40am:

I have checked some references, it seems HFSS cannot simulate the active circuits (am I right?).

Right.

Jack wrote on Oct 12^th, 2009, 2:40am:

So I have to export the antenna from HFSS, then import it into Cadence.

What do you mean by "Cadence" ?
Use correct terminologies with full description.
Even if you mean ADE of Cadence, there are many simulator engines available in Cadence ADE.

Jack wrote on Oct 12^th, 2009, 2:40am:

1. How can I export the antenna from HFSS, in which file format, it can match with cadence?

Again there are many simulator engines available in Cadence ADE.

However if you mean Cadence Spectre, "Citi File" Format or "Touchstone" Format is available even in Cadence Spectre.

Jack wrote on Oct 12^th, 2009, 2:40am:

2. If I add the antenna into cadence successfully, how should I build the testbench, because usually we use the port as the input, but if antenna is in the front of LNA, which kind port should be in the front of antenna (should the port with series resistor, like 50ohms)?

Jack wrote on Oct 12^th, 2009, 6:14am:

Third, assume the antenna component is added into the cadence, how to add the signal source to simulate the antenna with LNA ? Because for LNA, we can use the "port" from cadence analoglib, but if antenna is in front of LNA, which kind port I can use to start the simulation.

See http://www.designers-guide.org/Forum/YaBB.pl?num=1256313008/2#2

Jack wrote on Oct 12^th, 2009, 2:40am:

3. Compare HFSS with ADS, which one can give the easier solution?

Do you undertstand Agilent ADS surely ?
If you compare Ansoft HFSS with Agilent's Products, you have to pick up EMPro(EMDS, AMDS) and Momentum not ADS.
For antenna application, Agilent AMDS is suitable than Ansoft HFSS or Agilent EMDS.
If your antenna is a planar one such as patch antenna, Momentum is suitable.

Jack wrote on Oct 12^th, 2009, 6:14am:

In HFSS, as I know, I can export the return loss (S11), the impedance, and the antenna gain.

Do you have basic knowledge of RF circuit theory surely ?
S11 is completely equivalent to impedance.

Have you been able to understand the following ?
http://www.designers-guide.org/Forum/YaBB.pl?num=1234783833/12#12

Jack wrote on Oct 12^th, 2009, 6:14am:

First, is there an component in Cadence can import these 3 parameters (S11, gain, impedance) at the same time to perform the characteristics as an antenna?

Jack wrote on Oct 12^th, 2009, 6:14am:

Second, antenna just has S11 parameter, it doesn't have S21, S12, and S22, is it enough to just use S11 to represent the performance of return loss and impedance of antenna together? If S11 can perform impedance of antenna, then I just need to import the S11 and gain of the antenna.

Again do you have basic knowledge of RF circuit theory surely ?
S11 is completely equivalent to impedance.
Do you understand a definition of antenna gain surely ?

RX antenna gain is treated as EMF voltage or available power.

The followings are general notes.

- Use correct terminologies.
� � - Warnigns are different from Errors.
� � - ADS is not name of simulator.
� � - There is no tool which name is Cadence.
� � - All gains in Direct Plot of Cadence ADE are "right", "true" and "practical" voltage gain.
� � - MATLAB are different from Simulink.

- Learn measurements using actual instruments. Not "EDA Tool Play".

« Last Edit: Nov 3^rd, 2009, 6:37am by pancho_hideboo »

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http://www7.plala.or.jp/ungeromeppa/flash/kita.html
http://www.youtube.com/watch?v=mjIxGh55bMM&feature=related

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Jack

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Re: How to import antenna model from HFSS to Cadence?
Reply #3 - Feb 12^th, 2010, 1:11am

Hello, Pancho_hideboo

Thank you very much for your reply!

Now I am a little clear with the antenna. Actually I just want to try to use a narrow-band antenna to receive a wideband-signal. Hence I post some questions about the return loss of the antenna.

At the begining, I don't understand how the antenna works well. I misunderstand that the return loss can express the antenna completely. Therefore I want to get the S2P file, because I want to add the antenna as a two-port device in Cadence, then I can add the antenna between the signal source and the LNA, try to find it is possible to use the narrowband antenna to receive the wideband signal. I am sure the performance will decrease, but I want to know how much the performance will decrease.

Now I understand the return loss for the antenna is only existing between the antenna itself and the feed point. Also the S11 cannot represent the antenna completely, because the radiation efficiency is the key parameter. Now I am reading more materials about the antenna, then I will try to find the relation between the radiation efficiency and the frequency range first. After it, I will try to make the matching network to realize the impedance matching. It seems the S2P is not important for me at present, because I don't plan to design the on-chip antenna.

Thank you very much for your kindnes and patient.

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pancho_hideboo

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Re: How to import antenna model from HFSS to Cadence?
Reply #4 - Feb 12^th, 2010, 1:25am

Jack wrote on Feb 12^th, 2010, 1:11am:

I misunderstand that the return loss can express the antenna completely.
Therefore I want to get the S2P file,
because I want to add the antenna as a two-port device in Cadence,

Your sentences are contradicting completely regarding your requirement for S-parameters.

Describe correctly.

Again what do you mean by "Cadence" ?
Use correct terminologies with full description.

The followings are general notes for you.

- Always describe vendor's name which you use as tool or simulator.
- There are many simulators which have analyses called as PSS, PAC and Pnoise.
- Describe in detail with using correct terminologies.
- Warnigns are different from Errors.
- ADS is not name of simulator.
- There is no tool which name is Cadence.
- Don't use Direct Plot of Cadence ADE blindly without knowing definition.
- All gains in Direct Plot of Cadence ADE are "right", "true" and "practical" voltage gain.
- Don't mix up Simulation with Post Processing. They are completely different phase.
- MATLAB are different from Simulink.
- Learn measurements using actual instruments. Not "EDA Tool Play

Jack wrote on Feb 12^th, 2010, 1:11am:

then I can add the antenna between the signal source and the LNA,

It seems that still you can not understand definition of antenna gain as well as very basic theory of RF.

http://www.edaboard.com/ftopic379300.html
Why do you think |S11|²+|S21|²=1 ?
Do you understand unitary matrix condition for S-parameters ?

http://www.edaboard.com/ftopic380909.html
Quote:

Therefore I guess maybe when we start to measure the antenna,
first we use a single end to differential transformation, like the 180degree hybrid coupler,
then the one port antenna has two port.
Then we can measure the antenna using network analyzer.

Very amazing !!
You are completely misunderstanding characterization of antenna.

Learn actual measurement of antenna gain.
Antenna is reciprocal regarding RX and TX.

Also see http://edocs.soco.agilent.com/display/ads2009/LOS+Link+%28Line-Of-Sight+Antenna+...

« Last Edit: Feb 12^th, 2010, 3:38am by pancho_hideboo »

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

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