+ Post New Thread
Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 21 to 40 of 44
  1. #21
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    thank you very much for your kind guidance, Dr Volker. I Hope we can hire you as a consultant in the future. have a great day ahead.

    - - - Updated - - -

    i have another question. can we do design LTCC implementation in ADS?



  2. #22
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by pragash View Post
    can we do design LTCC implementation in ADS?
    Sure. We used Sonnet EM and Empire 3D EM, but basically any layout tool plus EM solver is possible.



  3. #23
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    mistake.. pls ignore

    - - - Updated - - -

    dr volker,
    i have one last question. im getting different inductance when i simulate using a different set of formulas. Please let me know which one is correct and why?

    Click image for larger version. 

Name:	5.png 
Views:	9 
Size:	93.0 KB 
ID:	151690

    results and formulas are attached side by side. the 1st formula is from ADS template.

    - - - Updated - - -

    Click image for larger version. 

Name:	6.png 
Views:	5 
Size:	62.7 KB 
ID:	151691

    ADS template have two method. extracting ind from Y11 and also Y12! both giving totally different results. Y11 shows -ve inductance whearas Y12 shows positive! which one to believe!

    - - - Updated - - -
    Last edited by pragash; 11th March 2019 at 19:19.



  4. #24
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    There is no "correct" or "wrong" equations, they are valid under certain conditions, as mentioned in the ADS template.

    Assume you have an inductor represented by a pi model, with series RL and shunt C to ground. You can then extract the pure L from the series path (excluding shunt effects) or the effective series inductance (including the effect from shunt components), or the effective input inductance into one terminal when the other terminal is shorted. You then get 3 different curves. All are valid, just different what you consider "the inductance". So you need to decide what value is relevant for your design use.


    1 members found this post helpful.

    •   AltAdvertisment

        
       

  5. #25
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by pragash View Post


    Click image for larger version. 

Name:	6.png 
Views:	5 
Size:	62.7 KB 
ID:	151691
    this inductor connected in series and not shunt to ground. Pure inductance and resistance extraction (Y12) shows +ve ind which is correct. shunt to ground inductance (Y11) shows negative inductance which is not my case.

    - - - Updated - - -

    Quote Originally Posted by pragash View Post

    Click image for larger version. 

Name:	5.png 
Views:	9 
Size:	93.0 KB 
ID:	151690
    this is a differential measurement of the inductor using reactance (imag(Z)). its only valid for differential configuration which is also not applicable for me. the best is two port measurement.



  6. #26
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by pragash View Post
    this inductor connected in series and not shunt to ground. Pure inductance and resistance extraction (Y12) shows +ve ind which is correct.
    But your inductor has parasitics: capacitance to ground.

    Quote Originally Posted by pragash View Post
    shunt to ground inductance (Y11) shows negative inductance which is not my case.
    That is possibly correct due to parasitics. Can you upload the inductor *.s2p, so that we extract the equivalent circuit model?

    Quote Originally Posted by pragash View Post
    this is a differential measurement of the inductor using reactance (imag(Z)). its only valid for differential configuration which is also not applicable for me. the best is two port measurement.
    I agree that you should use the full S2P data in circuit simulation. I just tried to explain why there is more than one correct answer regarding "the inductance value".


    1 members found this post helpful.

  7. #27
    Super Moderator
    Points: 252,712, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    44,024
    Helped
    13394 / 13394
    Points
    252,712
    Level
    100

    Re: need 7pF to 10pF at 2.5GHz

    I think the problem is not considering the prerequisites of ADS distributed components. MSIND is a microstrip inductor, it's referring to a MSUB microstrip substrate definition creating a respective shunt capacitance. Reading the ccdist manual thoroughly should clarify everything.

    Place a lumped inductor, e.g. AIRIND1 model and both setups should give equal inductance.


    1 members found this post helpful.

  8. #28
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by FvM View Post
    Reading the ccdist manual thoroughly should clarify everything.

    .
    could you please clarify what is ccdist manual?



  9. #29
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Can you upload the inductor *.s2p so that we have a useful data basis for discussion?


    1 members found this post helpful.

    •   AltAdvertisment

        
       

  10. #30
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    Dr.Click image for larger version. 

Name:	coil.png 
Views:	5 
Size:	15.9 KB 
ID:	151761 Volker,
    actually, I don't know how to generate an s-parameter file from the ADS. due to that, i sending you my coil parameters. you can simulate it and get the S-parameters. sorry for the inconvenience caused.



    •   AltAdvertisment

        
       

  11. #31
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by pragash View Post
    I don't know how to generate an s-parameter file from the ADS.
    In the ADS data display menu: Tools > Data File Tool
    This can create SnP from simulation dataset

    Click image for larger version. 

Name:	datatool.PNG 
Views:	3 
Size:	20.6 KB 
ID:	151770


    1 members found this post helpful.

  12. #32
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    thank you so much Dr. Volker. i have created s2p file. please refer below.

    coil.rar



  13. #33
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Data starts at 2.3GHz, which is not enough to extract a model. Please provide wideband data that goes down to DC.


    1 members found this post helpful.

  14. #34
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    attached the s2p as requested. thanks.

    coil_2.rar



  15. #35
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Indeed, your inductor has enough shunt capacitance to ground to become capacitive in some port configurations. Here is a simple pi model, extracted from your S2P:


    .subckt SON3_38 1 2 REF
    C_C1 1 REF 0.109335pf
    C_C2 2 REF 0.105086pf
    L_L1 1 3 63.69988nh
    R_RL1 3 2 1.0e-5
    .ends SON3_38

    If we evaluate Y11 (port 1 input impedance with port 2 shorted to ground) it looks capacitive at high frequency because we then have 63.7nH || 109fF.
    If we use the differential port configuration, we have a higher SRF because then 63.7nH || (109fF in series with 109fF)

    Click image for larger version. 

Name:	ind1.PNG 
Views:	3 
Size:	29.8 KB 
ID:	151799
    Click image for larger version. 

Name:	ind_testbench.PNG 
Views:	2 
Size:	17.8 KB 
ID:	151798


    1 members found this post helpful.

  16. #36
    Super Moderator
    Points: 252,712, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    44,024
    Helped
    13394 / 13394
    Points
    252,712
    Level
    100

    Re: need 7pF to 10pF at 2.5GHz

    could you please clarify what is ccdist manual?
    ccdist = "Circuit Components Distributed Components" ADS manual



  17. #37
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by volker@muehlhaus View Post
    Indeed, your inductor has enough shunt capacitance to ground to become capacitive in some port configurations. Here is a simple pi model, extracted from your S2P:


    .subckt SON3_38 1 2 REF
    C_C1 1 REF 0.109335pf
    C_C2 2 REF 0.105086pf
    L_L1 1 3 63.69988nh
    R_RL1 3 2 1.0e-5
    .ends SON3_38

    If we evaluate Y11 (port 1 input impedance with port 2 shorted to ground) it looks capacitive at high frequency because we then have 63.7nH || 109fF.
    If we use the differential port configuration, we have a higher SRF because then 63.7nH || (109fF in series with 109fF)

    Click image for larger version. 

Name:	ind1.PNG 
Views:	3 
Size:	29.8 KB 
ID:	151799
    Click image for larger version. 

Name:	ind_testbench.PNG 
Views:	2 
Size:	17.8 KB 
ID:	151798
    Dr Volker, how did u extract the exact C associated with the coil?



  18. #38
    Advanced Member level 5
    Points: 12,485, Level: 26

    Join Date
    Apr 2014
    Posts
    1,934
    Helped
    791 / 791
    Points
    12,485
    Level
    26

    Re: need 7pF to 10pF at 2.5GHz

    Quote Originally Posted by pragash View Post
    Dr Volker, how did u extract the exact C associated with the coil?
    I went the easy way and used the Sonnet PI model extraction.
    You should be able to get a similar answer in ADS by extracting the shunt path elements. For your convenience, I have posted some code from my Inductor Toolkit model extraction.

    Y = stoy(S)
    omega = indep(S) * 2 * pi
    Cshunt_port1= 1 /(-omega*imag(1/(Y(2,1)+Y(1,1))))
    Cshunt_port2= 1 /(-omega*imag(1/(Y(2,1)+Y(2,2))))

    Click image for larger version. 

Name:	cshunt.PNG 
Views:	7 
Size:	43.0 KB 
ID:	151835
    Last edited by volker@muehlhaus; 18th March 2019 at 09:00.


    2 members found this post helpful.

  19. #39
    Full Member level 1
    Points: 707, Level: 5

    Join Date
    Jun 2018
    Posts
    119
    Helped
    11 / 11
    Points
    707
    Level
    5

    Re: need 7pF to 10pF at 2.5GHz

    Reading these makes me sad about my job. How can I find people/material to help me learn about these stuff?

    I am currently suffering from a similar phenomeon on extracting the parasitic values of (lumped elements+TLIN) in matching circuit. I need to model my elements and TLIN's in a better way; but have no clue on where to start.



  20. #40
    Advanced Member level 1
    Points: 4,650, Level: 16

    Join Date
    Jul 2005
    Location
    Oakland
    Posts
    452
    Helped
    58 / 58
    Points
    4,650
    Level
    16

    Re: need 7pF to 10pF at 2.5GHz

    what is the best impedance we should design the interconnect so that it won't form an inductor? 50ohm? or 75ohm?



    •   AltAdvertisment

        
       

--[[ ]]--