Search:

Type: Posts; User: volker@muehlhaus

Page 1 of 20 1 2 3 4

Search: Search took 0.05 seconds.

  1. 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...
  2. 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.
    ...
  3. 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...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. 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.
  10. 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.
  11. 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...
  12. 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,...
  13. 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...
  14. 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...
  15. 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 ....
  16. 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...
  17. Closed: Re: When simulating center tapped inductor in ADS

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

    154876
  18. Closed: Re: When simulating center tapped inductor in ADS

    Then I think your math is wrong for 3-port simulation. It is valid for 2-port simulation.
  19. Closed: Re: When simulating center tapped inductor in ADS

    There is no port 3 in your linked post. Which is fine.

    - - - Updated - - -



    I am working on these inductor simulations for many years, and never heard that. The center tap is a virtual...
  20. Closed: Re: When simulating center tapped inductor in ADS

    Leave the port impedances set to 50 Ohm. The circuit simulator later takes care of the calculating the voltages and currents for the external impedances connected to the model. S-parameters don't...
  21. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    I have no advice for coupler layouts, because I've spent most of my time in simulation (not design). My idea was just to make it more symmetric. The 135° looks a bit suspicious to me, with possibly...
  22. Closed: Re: Single conductor inside hollow conductor

    "Single conductor inside hollow conductor" sounds like coax cable, in which case the shield is connected as the return path. But maybe your setup is different. In any case, there is capacitance...
  23. Closed: Re: Measuring propagation loss between two dipoles over free space

    Let's do a quick calculation: 6ft is 1.83m. At speed of light, the signal takes 1.83m/3e8m/s = 6.1ns so the 204ns time limit is fine. So this is not the issue.

    Maybe you should talk to CST support.
  24. Replies
    18
    Views
    727

    Closed: Re: Resistance Flicker Noise Question

    Interesting, thank you!
  25. Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

    Here are results for your latest DXF layout:

    154849



    I would start from scratch and re-design the layout, without all those asymmetries. Equal lengths and a symmetric layout, instead of that...
Results 1 to 25 of 500
Page 1 of 20 1 2 3 4