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Type: Posts; User: volker@muehlhaus

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  1. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Have you read my link above?

    Section 4.3 EMC Assessment
    4.3.1 General Concept

    The EMC assessment needs to take into account all normal intended operating conditions of the apparatus. In cases...
  2. Closed: Re: Keysight ADS ground connection in schematic not reflected in layout

    I cannot recommend to do that, because you EM simulate something that you can't build. The MLSC mode automatically creates a "2D sheet" via at the end of the MLSC. If that connection is missing in...
  3. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    treez, please let me know what company you work for, so that I can stay away from products that you designed. You always try to interpret specs and regulations to your liking.
  4. Closed: Re: PCB and schematic simulation for CE with CST

    Yes, that creates a connection from the ports plus terminal to the ports local reference.



    If your port represents a series element, then both is wrong. You need to probe voltage against the...
  5. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    I looked at LED driver EMC regulations a while ago. From what I remember, you need to test the worst case that is likely in real operation.

    https://ec.europa.eu/docsroom/documents/33601
  6. [SOLVED]Closed: Re: Assigning boundary and Lumped port to 3D spiral coils in HFSS

    Let me add: a port has + and - terminal. You have one TX port and one RX port.
  7. [SOLVED]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.
  8. 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
  9. 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...
  10. 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.
  11. [SOLVED]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).
  12. 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...
  13. Closed: Re: [HFSS] What does N/A mean for delta S?

    Additional meshing frequency oder additional convergence criteria?
  14. 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...
  16. 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.
  20. Closed: Re: How can we measure magnetic field strength generated by an antenna?

    n = number of turns of the pickup coil
  21. 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.
  22. [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.
  24. [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...
  25. [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...
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