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Type: Posts; User: volker@muehlhaus

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  1. Closed: Re: Assigning port and boundaries to 3D spiral coil in HFSS

    As I wrote: one lumped port for each coil, between the two ends of the wire, so that current can flow from the port through the coil.
  2. Closed: Re: ELF antenna and transmitter design

    That's a good keyword to find online calculators, this one looks useful to me for estimating a spiral coil configuration:
    http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html
  3. Closed: Re: ELF antenna and transmitter design

    Yes, the magnetic field isn't where you expect it. You need a flat coil.

    For field strength, it depends how much power is available. For a battery operated device with continuous operation, it...
  4. Closed: Re: ELF antenna and transmitter design

    At these frequencies, your "wire" is only useful to create an electric field. To create your ELF magnetic field, you need a closed loop indeed.
  5. Closed: Re: Assigning boundary and Lumped port to 3D spiral coils in HFSS

    The problem is what the message says: each port must be between two conductors (the two ends of the coil).
  6. Closed: Re: [HFSS] What does N/A mean for delta S?

    I have difficulties to believe that - look at deltaS which jumps back to very large values after the N/A in pass 8.
    I'm not an HFSS user, but I only see that behaviour in other FEM if there is...
  7. Closed: Re: [HFSS] What does N/A mean for delta S?

    Additional meshing frequency oder additional convergence criteria?
  8. Closed: Re: [HFSS] What does N/A mean for delta S?

    For the first pass at that frequency, there is no previous S-parameter value to compare with, so deltaS cannot be calculate -> not applicable.
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    Closed: Re: reason for 50 Hz ac current

    Great link, thank you!

    More examples on unusual frequency: here in Germany, railway for historic reasons use 16.7 Hz instead of the usual 50 Hz, because in the early days high power electric...
  10. Closed: Re: Doubts regarding MMIC LNA design usingKeysight Technolo Advanced Design System (

    Can you back to your university to attend the related classes? Then you should be able to learn this stuff within a year or so. With integrated circuit design, you need a much more detailed...
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    Closed: Re: HFSS vs. Momentum accuracy

    I'm not sure what you mean. Momentum uses OPEN boundary condition on the sides. For a PEC boundary at the top or bottom, you can set that boundary in the Momentum substrate definition.


    ...
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    Closed: Re: HFSS vs. Momentum accuracy

    In my experience: yes, because it is more efficient and has less chances for mistakes in modelling.



    That indicates that one or both models are not accurate enough. This is not a tool problem,...
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    Closed: Re: HFSS vs. Momentum accuracy

    No. Momentum uses a different method to solve Maxwell's equations (Method of Moments) that is more efficient for such planar models. HFSS uses a more generic method.
  14. Closed: Re: How can we measure magnetic field strength generated by an antenna?

    n = number of turns of the pickup coil
  15. Closed: Re: Deviation between simulation and measurement of matching circuits

    To be more specific: different reference plane, i.e. extra line length included in measurement. Test your measurement response whith a known device (open or short) and see what you get in Smith chart.
  16. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    No, Brad ist correct: the magnitude of R and X are equal in his left testcase, and current is equal, so indeed there is 0.7V across each of the components. But these voltages have a 90° phase offset,...
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    Closed: Re: very uneven power divider

    What is the coupling ratio? Maybe it's easier to just use a resistive divider in parallel to the main line, if the coupling is that small. The resulting mismatch is small then.
  18. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    Here is the mistake in interpretation of your voltage divider experiment:

    You expect the output voltage to be half the total voltage, because R and X are equal.

    But that's wrong. The voltage...
  19. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    Are you new to the concept of complex impedance? In the original post, there is a proper specification of complex impedance (real part from 50 Ohm termination, imaginary part from capacitor) so I'm a...
  20. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    No. Impedance is capacitor voltage divided by capacitor current, and then we get 77 Ohm from your experiment.

    156091
  21. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    chiques, my comment was for BradtheRad and his comment. He missed that you specified the proper complex value.
  22. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    Why do you confuse people if you don't understand the Smith Chart, and how to read it?
    The original question was clear: 50.04 -j77.16
  23. [SOLVED]Closed: Re: Calculate Capacitance Value from Smith Chart

    https://www.allaboutcircuits.com/tools/capacitor-impedance-calculator/
  24. Closed: Re: Microstrip to layout in ADS for power amplifier design

    You're discussing the wrong workflow. He uses a complete device, and doesn't design his own chip.

    - - - Updated - - -



    Look up the footprint size in datasheet and arrange input & output...
  25. Closed: Re: Microstrip to layout in ADS for power amplifier design

    It seems he relies on auto-generated layout (from schematic) and doesn't know how to place components or artwork in layout manually. So in that case, having the component footprint will help in...
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