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  1. Closed: Re: Balun design gives box resonance error in Sonnet

    Wait, why just the feed structure for this box mode test ?




    I am not sure. I need to email the original authors of the paper regarding this. I will get back to this post once they reply.
    ...
  2. Closed: Re: Balun design gives box resonance error in Sonnet

    I downloaded your zip file but I still find that box resonance errors are still not suppressed as you had stated in post #7

    Did I miss anything ?

    https://i.imgur.com/2XFed11.png
  3. Closed: Re: Balun design gives box resonance error in Sonnet

    Free space as in vacuum ? then this will only work well within simulation.

    I already tried to increase the Air layer height to 40mm , but I just got more box resonance errors.
  4. Closed: Re: Microstrip High- and Low-Impedance Short-Line Sections

    There is a typo mistake for ABCD matrix for π-circuit network at Figure 4.7(b)

    Please see the correction below:

    https://i.imgur.com/IrNmN5r.png


    Ok, now to more detailed part:

    How to...
  5. Closed: Re: Balun design gives box resonance error in Sonnet

    I have already tried modifying the box size, but it does not really help.

    https://i.imgur.com/BHWrq62.png
  6. Closed: Re: Balun design gives box resonance error in Sonnet

    Well, this is not planar marchand balun. This balun topology does not require vias connections to ground.

    By the way, you can just run the Multi-Section_Coupled_Line_Balun.son design file using...
  7. Closed: Balun design gives box resonance error in Sonnet

    Why does this balun design (A 0.8–8 GHz Multi-Section Coupled Line Balun) give box resonance error in Sonnet ?

    Note: Just rename the attached Multi-Section_Coupled_Line_Balun.txt to...
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    Closed: Re: LNA circuit not working

    @frankrose

    Any comment on the .noise analysis simulation result below ?

    https://i.imgur.com/4qKee2h.png
  9. Closed: Why Z and Y matrices must be pure imaginary for reciprocal lossless N-port junction ?

    For a reciprocal lossless N -port junction,

    1) Why is Pavg = 0.5*[V] t [ I ] * instead of Pavg = 0.5*[V] * [ I ] t or Pavg = 0.5*[ I ] t [V] * ?

    2) Why [V] = [Z][ I ] instead of [V] = [ I...
  10. Closed: Re: Microstrip High- and Low-Impedance Short-Line Sections

    The following is the derivation process for expression 4.50

    ABCD matrix for transmission line at Figure 4.7(a)

    https://i.imgur.com/6FXNyjF.png

    ABCD matrix for π-circuit network at Figure...
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    Closed: Re: LNA circuit not working

    I have put everything under https://github.com/promach/LNA

    Any advices or comments on the TODO list within the github README ?
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    Closed: HF Upconverter Circuit Question

    What are the purposes of {L5, R5} , {C10, C11} , {R2, R4} in this HF upconverter circuit ?

    https://i.stack.imgur.com/QQCSw.png
  13. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    I have made both the coupled lines matching length and width. However, I am still not getting 180 degrees phase response.

    Why ?

    I have attached the dxf file as zip at the end of this post
    ...
  14. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Yes, you are right.

    See New Design Formulas for Impedance-Transforming 3-dB Marchand Baluns

    I presume that we need to include both source impedance (Rr) and load impedance (RL) in EM layout...
  15. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Alright. I will redo the layout. To be frank, that 135 degree turn is to allow space for isolation circuit between port 2 and port 3. Please advise.

    Besides, how does the length of the coupled...
  16. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Why does the balun phase deviates away from 90 degrees and -90 degrees as HFSS sweeps up the frequency ?

    Can we do anything to the balun layout in order to make this issue less serious ?

    The...
  17. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    How is this related mathematically to Zin=Z0* [ ZL+j*Z0*tan(theta)] / [ Z0+j*ZL*tan(theta)] ?
  18. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Zin=Z0* [ ZL+j*Z0*tan(theta)] / [ Z0+j*ZL*tan(theta)]

    Someone told me to use the above expression to understand why balun needs via. Any advices ?

    Besides, why arg(S_21) - arg(S_31)...
  19. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Let me investigate more about the ground layer.

    https://i.imgur.com/2XxJ5gz.png

    - - - Updated - - -

    Ok, I have made the balun works.

    The real reason is due to the via connectivity to the...
  20. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    See the layer stackup at post #44
  21. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    In your post #30 , you did not show the balun phase, S21 and S31


    Note that HFSS simulates the PCB with air below and above it, hence the large box enclosing the PCB within


    Overall view
    ...
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    Closed: Re: LNA circuit not working

    I could not find such narrowband matching circuit topology from section 3.4.3 of book RF circuit design 2nd edition by Richard LI

    https://i.imgur.com/dUXi4Aw.png





    - - - Updated - - -
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    Closed: Re: LNA circuit not working

    What I do not understand is the strange AC response in the previous post just above with a sharp magnitude dip and abrupt 180 degrees phase shift at 2.9GHz


    The transient response looks normal...
  24. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    @volker@muehlhaus

    I think I know why HFSS gave completely different result compared to ADS for the same DXF file.

    DXF is only 2D.
    I suppose ADS automatically added the 3D height for the...
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    Closed: Re: LNA circuit not working

    @frankrose

    I am doing this at 2.4GHz

    See the following snippet about L1 and C1 parallel network. I am not sure about C3 though.

    https://i.imgur.com/4mqh1AZ.png

    ...
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