Low Q Matching Network Design

Discussion in 'The Projects Forum' started by harvester, Oct 21, 2014.

  1. harvester

    Thread Starter New Member

    Mar 12, 2014
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    Good day! I am currently designing a matching network with source resistance of 50 ohms and load resistance of 3600 ohms. I am planning to use the Low-Q Matching Network design, where L networks are connected or cascaded, to increase the bandwidth of the network. My question is, is there a limit on how many L matching networks I can connect? What are the drawbacks of having too many L networks in the design?
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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  3. harvester

    Thread Starter New Member

    Mar 12, 2014
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    Thanks, I use that also.

    I am designing at 2.4GHz. There is no specific value yet for the bandwidth, but I want it to be as wide as possible. So, is there a limit on how many L networks I can connect? And what are the trade offs of having too many cascaded L networks. Thank you.
     
  4. alfacliff

    Well-Known Member

    Dec 13, 2013
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    when you cascade l networks, they interact, and ou have to compensate for that. also loss increases with number of networks. badwidth is going to be a necessity to calculate the filter.
     
  5. harvester

    Thread Starter New Member

    Mar 12, 2014
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    What do you mean by interact? And what will be compensated? Thank you.
     
  6. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the reactance of one l network will be connected to the next, and so forth. there isnt a way to isolate the reactance of one from another. compensation if for connecting one to another l network, you cant use the values for one l when you have two or more connected.
     
  7. Lestraveled

    Well-Known Member

    May 19, 2014
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    You can greatly reduce the interaction by putting a gain stage between each section.
     
  8. Papabravo

    Expert

    Feb 24, 2006
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    In this frequency range lumped component values may unsuitable. Are you familiar with microstripline design?

    #1 Google hit
    http://www.qsl.net/va3iul/Microstrip_Stripline_CPW_Design/Microstrip_Stripline_and_CPW_Design.pdf
     
  9. DickCappels

    Moderator

    Aug 21, 2008
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    If you use many sections in your filter, you might find that you need to add shielding between sections, and of course, the more stages, the greater the power losses.

    As per PappaBravo, you will probbaly find transmission line matching techniques much easier to successfully deal with.
     
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