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Type: Posts; User: volker@muehlhaus

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  1. Closed: Re: microstrip low pass filter design issues with sonnet

    Z0 is related to the line cross section. For a lossless line it is sqrt(L'/C') where L' is inductance per unit length and C' is capacitance per unit length. So you can see that line impedance itself...
  2. Closed: Re: microstrip low pass filter design issues with sonnet

    Sure, those are the 50 Ohm feed lines. Very typical. No length because they are 50 Ohm and length doesn't matter.
  3. Closed: Re: microstrip low pass filter design issues with sonnet

    You design the filter for a given source and load impedance, here: 50 Ohm. No additional impedance transformers needed.

    Input and output lines are designed for those 50 Ohm, which is the standard...
  4. Closed: Re: Difference in results of HFSS and ADS

    That looks ok.

    We don't have enough information to see what your mistake was.

    A popular mistake is to place a port on the edge of a wide ground polygon, so that the entire edge length becomes...
  5. Closed: Re: Balun design gives box resonance error in Sonnet

    Sorry, no idea, I never used Controlled Impedance Analyzer and don't know what method they use.
  6. Closed: Re: How to include RF Transistor Vendor Kit in Advanced Designed Design(ADS)

    What exactly?
  7. Closed: Re: Balun design gives box resonance error in Sonnet

    How did you calculate the width and gap in the coupled line sections?
    The coupled line sections all line up exactly at the outside, so are the gaps actually calculated?

    155090

    ~~

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

    Ok, then the ground connection by touching the box walls is perfectly correct!

    The substrate is also specified: er=4.2 with 1.5mm thickness (not 2.0mm as in your Sonnet model). But then, for the...
  9. Closed: Re: Balun design gives box resonance error in Sonnet

    This uses the feed structure as a "probe" to excite the box modes. Sonnet box = cavity resonator, feed lines couple into that resonator. If there is no spurious transmission in that case, your actual...
  10. Closed: Re: Balun design gives box resonance error in Sonnet

    Yes, you miss something. That dialog shows possible box modes based on box dimensions. It does not evaluate if the box modes are actually excited, or surpressed by free space absorbing boundary.
    ...
  11. Closed: Re: Why does my homemade Yagi wifi antenna perform so poorly?

    Yes, I understand this isn't your design, but both have "uncontrolled" wire length of several mm length between coax and dipole , which means several nH series L, which menas some dozen Ohm of series...
  12. Closed: Re: Balun design gives box resonance error in Sonnet

    Circuit > Box > Covers

    Yes, the metal box causes box resonances and that is a real effect. The practical solution is the same what "free space" setting in Sonnet does: using absorbing material at...
  13. Closed: Re: Balun design gives box resonance error in Sonnet

    You have multiple mistakes in your model.

    At least you have now removed the short circuit between the feedline at port 3 and the box wall.
    The next question is if the two lines left and right...
  14. Closed: Re: Balun design gives box resonance error in Sonnet

    I don't need Sonnet Lite because I have Sonnet Professional and was part of the Sonnet support team for many years. That's why I say your model looks totally wrong!



    Sure, but you have several...
  15. Closed: Re: Balun design gives box resonance error in Sonnet

    Do you realize that the Sonnet box wall is a metal boundary? Like a metal box? You have a line from port 3 directly at the box wall, that looks wrong to me. Also, the lines at port 1 might not be...
  16. Closed: Re: Why does my homemade Yagi wifi antenna perform so poorly?

    I agree that usually the folded dipole has some 4:1 balun, but it's not always true. The dipole inside a yagi isn't the same as that dipole stand-alone. The impedance is influenced by the reflectors...
  17. Closed: Re: Why does my homemade Yagi wifi antenna perform so poorly?

    For such an antenna, you need to be much more precise with dimensions. I don't think you have a chance to realize it with your low mechanical precision.
  18. Closed: Re: problem: coupling coefficient for two hairpin resonators

    Those are really high Q resonators. Maybe your conductor losses and/or substrate losses are too high, so that possible Q is too low.
  19. Closed: Re: CST accuracy control beyond the mesh density

    That's obviously wrong. For calculating radiation efficiency, the total radiated power is calculated by integrating over all the boundaries. I'm not a CST user, but in some EM tools there are...
  20. Closed: Re: CST accuracy control beyond the mesh density

    Your question is not clear.

    If you have >100% radiation efficiency, something is obviously wrong.

    If you have a lossless antenna model, radiaton efficiency must be 100%.
    For a lossy antenna,...
  21. Closed: Re: When simulating center tapped inductor in ADS

    What post and P2 do you refer to? In my post #11 the center tap is at Port 3 and that's floating in this comparison.

    The difference between single ended Q and differential Q is also seen for the...
  22. Closed: Re: When simulating center tapped inductor in ADS

    My test was to check if pancho's equations also work to create differential data from 3-port S-params where the center tap is connected. That indeed works.

    Here is the comparison of single ended...
  23. Closed: Re: Single conductor inside hollow conductor

    Your setup is unclear, as mentioned above. The normal use of coax is to have current on both inner and outer conductor, with opposite direction. Signal path and return path, you know ....
  24. Closed: Re: Simulation discrepancies between Sonnet (standalone) and Sonnet Cadence Interface

    Yes, but you would need to add margings to keep away the metal box walls. The Cadence interface will then add in feedlines with ref shift.



    Yes and yes.

    For such small L values where...
  25. Closed: Re: When simulating center tapped inductor in ADS

    I just tested it and confirm it works for 3-port simulation also. :thumbsup:

    154876
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