1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculating dimensions of a transformer on microstrip

  1. May 12, 2016 #1
    1. The problem statement, all variables and given/known data

    Using the graphs calculate lengths and widths of transformers (quarter wave) if they are realised as microstrip lines on a substrate that has Er=2 and height of 1.6mm at frequency 1.8GHz



    2. Relevant equations

    Guided wavelength = c/((Eef)^1/2)*f)



    3. The attempt at a solution

    Using the top graph Z1 =22.5ohm for Er=2 gives an w/h ratio of 10 therefore with a height of 1.6mm width would equal 16mm

    For length it would be 1/4 of a guided wavelengh.From the bottom graph using a w/h ratio of 10 then Eeff=2

    (3*10^8) /( (4*1.8*10^9) * (2)^1/2 ) =29.5mm

    For Z2 w/h ratio for 77.5ohm = 2

    w/h of 2 from graph gives Eeff of 1.8

    Width = 1.6*2 =3.2mm

    length =(3*10^8) / (4*1.8*10^9*(1.8)^1/2 ) = 31mm
  2. jcsd
  3. May 12, 2016 #2


    User Avatar
    Science Advisor

    Yup, I get the same answer using your Guided wavelength equation (which seems to be the one I remember.)
  4. May 13, 2016 #3

    Thanks for you r help Tom :)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Calculating dimensions of a transformer on microstrip