---
+ Post New Thread
Results 1 to 10 of 10
  1. #1
    Newbie level 4
    Points: 1,568, Level: 9
    nghalion's Avatar
    Join Date
    Apr 2006
    Location
    Egypt
    Posts
    5
    Helped
    2 / 2
    Points
    1,568
    Level
    9

    How can I extract resistance,capacitance,and inductance from S-parameters?

    Hi Guys...
    How can I extract resistance,capacitance,and inductance from S-parameters..
    I keep finding these papers and they all conatain this phrase "the S-parameters were fitted into an RLC circuit model"...I want to do the same thing to get the values of RLC of a structure modeled in HFSS..
    Please help

    Thank You

  2. #2
    Advanced Member level 3
    Points: 16,944, Level: 31

    Join Date
    Aug 2005
    Location
    INDIA
    Posts
    810
    Helped
    232 / 232
    Points
    16,944
    Level
    31

    s parameter to rlc model

    Hello nghalion,

    The attached document on TESTING S-PARAMETERS FOR TYPICAL PASSIVE CIRCUITS (3TestSpars4Circuits.pdf) discusses about this issue...

    You can do
    Effective Inductance (nH) of a Series RL network
    L(nH)=1.0E9 * imag( 1 / Y11) / ( 2*PI* FREQ )
    Series Inductance (nH) between any pair of ports assuming a PI-model
    L(nH)=-1.0E9 * imag( 1 / Y21) / ( 2*PI* FREQ )

    Effective Capacitance (pF) of a Series RC network
    C(pF)=-1.0E12 / ( 2*PI* FREQ * imag( 1 / Y11) )
    Series capacitance (pF) between any pair of ports assuming a PI-model
    C(pF)=1.0E12 / ( 2*PI* FREQ * imag( 1 / Y21) )


    ---manju---


    1 members found this post helpful.

    •   Alt7th February 2007, 09:13

      advertising

        
       

  3. #3
    Full Member level 6
    Points: 5,453, Level: 17
    madengr's Avatar
    Join Date
    Apr 2005
    Location
    Kansas City
    Posts
    394
    Helped
    107 / 107
    Points
    5,453
    Level
    17

    s-parameter to rlc model

    There are software packages that fit RLC equivalent circuits to S-parameters, such as http://www.emwonder.com/.

    Microwave Office and Sonnet will also. I believe Ansoft sells a seperate package to do this.

    Using good judgement you can come up with an equivalent RLC circuit by hand and run an optimizer to fit it to the s-parameters.



  4. #4
    Junior Member level 1
    Points: 3,076, Level: 13

    Join Date
    Sep 2001
    Posts
    17
    Helped
    2 / 2
    Points
    3,076
    Level
    13

    calculating rlc s-parameters

    the BoardSpice from Sigrity can fit very excellent results , then the extract RLC model can run under HSpice , try it
    But , do precisious measurement is a the first and the most important key Step !!


    1 members found this post helpful.

    •   Alt8th February 2007, 00:04

      advertising

        
       

  5. #5
    Newbie level 4
    Points: 1,568, Level: 9
    nghalion's Avatar
    Join Date
    Apr 2006
    Location
    Egypt
    Posts
    5
    Helped
    2 / 2
    Points
    1,568
    Level
    9

    fitting s-parameters into rlc

    I thank You all for ur replies..but I'm still a bit confused here..

    Exactly which parameters should I plot in HFSS (S, Y, or Z) and in what function (im, re, mag, dB..etc.) and at which frequencies should I apply the equations provided by Manjunatha_hv

    I provided the S-parameters (dB) earlier, and here is a pic of the project in HFSS..

    Thanx in advance



  6. #6
    Advanced Member level 3
    Points: 16,944, Level: 31

    Join Date
    Aug 2005
    Location
    INDIA
    Posts
    810
    Helped
    232 / 232
    Points
    16,944
    Level
    31

    r l c equivalent fitting

    Hello nghalion,


    Is this capacitive MEMS Switch or CPW structure ?...
    upload the DXF file with dielectric layer details I will try to help using may be Microwave Office or Sonnet ( if it is planar structure)...

    You need to plot Im of Y parameters to use with the mentioned equations....


    ---manju---



  7. #7
    Newbie level 4
    Points: 1,568, Level: 9
    nghalion's Avatar
    Join Date
    Apr 2006
    Location
    Egypt
    Posts
    5
    Helped
    2 / 2
    Points
    1,568
    Level
    9

    s-parameters rlc

    Hi manju,

    It's a capacitive shunt switch but this is not my original project. I'm working on this one for it's simplicity. Unfortunately I don't know how to to create a DXF file of it because the model was made in HFSS and no export to DXF option is available. I heard that it is possible to fit the S-parameters into RLC in MATLAB. I don't know if someone has a code for the operation but anyways, thanks alot for your help..

    nghalion

    Added after 3 minutes:

    Forgot to say that it's a capacitive Mems shunt switch positioned on top of a CPW..
    And I must find S-parameters in both Up-state and Down-state and the equivalent circuit model for each case..

    Thanks



  8. #8
    Junior Member level 1
    Points: 3,076, Level: 13

    Join Date
    Sep 2001
    Posts
    17
    Helped
    2 / 2
    Points
    3,076
    Level
    13

    Re: S-parameters to RLC

    exactly !!
    broadspice do great convert to RLC from S

    it is wonderful !!!



  9. #9
    Newbie level 4
    Points: 1,086, Level: 7

    Join Date
    Jan 2007
    Posts
    5
    Helped
    0 / 0
    Points
    1,086
    Level
    7

    Re: S-parameters to RLC

    Hi there,

    I am facing similar problem RLC extraction from S-Parameter. I understand that the inductance of a simple RF MEMS switch is abt 7pH for a 80um wide armature over a 60um/100um/60um CPW. However when I extract it using Sonnet with the effective inductance formula, the value is about 30pH.

    Can anyone please help to enlighten me on this issue?

    Thanks in advance.



  10. #10
    Member level 4
    Points: 1,852, Level: 10
    Achievements:
    7 years registered

    Join Date
    Nov 2006
    Location
    Rome
    Posts
    68
    Helped
    12 / 12
    Points
    1,852
    Level
    10

    Re: S-parameters to RLC

    you can see also here to find Y Z matrices and S-->Z

    http://www.uwaverf.altervista.org/in...d=48&Itemid=53


    1 members found this post helpful.

+ Post New Thread
Please login