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Type: Posts; User: volker@muehlhaus

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  1. Closed: Re: Power Gain and Voltage Gain of LNA

    Sweetheart, I knew you would start that discussion again, again, because you love to fill threads with self quotes. Have a great life!
  2. Closed: Re: Power Gain and Voltage Gain of LNA

    S-parameters are voltage ratios, not power, so it is 20log ()

    I would expect an LNA to operate at 50 Ohm load, so why do you look at gain into 1.3kOhm load?
  3. Closed: Re: DC blocking capacitors or interdigital capacitors at 24 GHz

    If the element passes 24GHz RF with good S11 and blocks DC, that should be fine. Once you have optimized the layout, you will have small series impedance. At lower frequencies, it will be...
  4. Closed: Re: DC blocking capacitors or interdigital capacitors at 24 GHz

    This is what a friend created 20 years ago, substrate quite similar to yours.
    Curves are simulated and measured S11 and S21.

    I cant share more details, but maybe this gets you started.

    153997
  5. Closed: Re: Questions for Dr. Mühlhaus Spiral Inductor Assistant for Sonnet

    I don't understand your question. My spiral tool for Sonnet creates a layout based on the dimensions that you - the user - enter into the tool. It gives you feedback on estimated inductance (using...
  6. Closed: Re: Questions for Dr. Mühlhaus Spiral Inductor Assistant for Sonnet

    Hello,

    I created this tool long ago and haven't used it for years, but will try to answer your questions.



    The simple reason is that layout code makes room for crossover, and doesn't check...
  7. Closed: Re: microstrip low pass filter design issues with sonnet

    You mean the Sonnet example shown above? That has narrow series lines (inductive) with an open ended line (capacitive) in the middle. So it is T configuration.
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    Closed: Re: Antenna efficiency from S11

    Reasonable matching of the antenna to your source is a requirement, so that you get your transmitter power into the antenna, at your frequency of interest.

    This doesn't tell anything about...
  9. Closed: Re: microstrip low pass filter design issues with sonnet

    Have a look at Nuhetz Filter Solutions synthesis, it's accurate and has a link to Sonnet.
    And get a large PCB if you're desiging for 100MHz. 8-O
  10. Closed: Re: Microwave Office CPW EM-Simulation

    Having some large vias somewhere (outside the meaningful current path) as shown in your screenshot should not have much effect anyway.

    Vias: the conducting side walls in EMSight will create a...
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    Closed: Re: Antenna efficiency from S11

    Actually, that antenna efficiency (percentage of power that is actually radiated) is a useful number and we use it in many projects. It's easy to obtain from simulation, not so easy from measurement...
  12. Closed: Re: microstrip low pass filter design issues with sonnet

    It's real. The filter response changes if you put the filter into a metal box of different height, even if you put some absorber at the top cover.
  13. Closed: Re: Using a diode connected transistor model in CST 3D simulation

    You should check if the excitation level can be changed without repeating the EM analysis of the linear passive model parts. It would be inefficient to repeat the EM calculation if only the diode...
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    Closed: Re: Using a 0db Attn as termination

    From your datasheet, that is a series of SMD attentuators. Different values including 0 dB can be used for post-layout level adjustment.

    The attenuator will improve matching by 2*A dB, where A is...
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    Closed: Re: Using a 0db Attn as termination

    What do you mean by 0dB attenuator? In your drawing, is that "0dB" device a ferrite isolator or why does it provide isolation?
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    Closed: Re: Broken RF ground plane

    Sounds reasonable, just connect top and bottom near the gap. Another option would be to place a capacitor with suitable SRF across the slot, or a 0R resistor, so that RF can pass.
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    Closed: Re: Dipole antenna input

    Yes, but that's not "clean" and if you have some length of line between the antenna, it will be part of the radiating structure and sensitive to the environment. In one my projects, I tried that but...
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    Closed: Re: Dipole antenna input

    Use a 1:1 balun from coax to symmetric (differential).
  19. Closed: Re: Response of the TLINE for different frequencies and lengths

    Don't feed the troll.

    - - - Updated - - -



    No, the frequency + phase delay in TLINE is only another way to specify the line length. So this should be constant during your frequency sweep.
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    Closed: Re: cadence to ADS EM simulation

    Do you work in EDA museum? We discussed VPCD end-of-life ten years ago.
  21. [SOLVED]Closed: Re: Drawing simple Data in Smith ADS smith Chart

    Surely learn difference between RF fundamentals and software implementation. The Smith chart is all about that background impedance grid - without that, it's just a polar plot of reflection factor.
  22. [SOLVED]Closed: Re: Drawing simple Data in Smith ADS smith Chart

    Do you understand normalized impedance? When Smith chart is teached at universities, you learn about the normalized impedance/admittance grid on the chart. There is no need for "marker calculation",...
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    Closed: Re: Antenna efficiency from S11

    You can't do that.

    From S11 data, you can't tell anything about radiated power vs. power loss in the antenna.
    If you have s11=0, this can be a perfect antenna or a 50 Ohm resistor, you can't...
  24. [SOLVED]Closed: Re: Drawing simple Data in Smith ADS smith Chart

    Sweetheart, calm down. Every RF engineer can read normalized impedance from Smith Chart.
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    Closed: Re: cadence to ADS EM simulation

    EM simulation in ADS (Momentum) is based on the layout, not based on other simulation results (S-parameters).
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