Transmission Line Theory problem

Discussion in 'Wireless & RF Design' started by ECE101, Dec 2, 2011.

  1. ECE101

    Thread Starter New Member

    Nov 25, 2011
    29
    0
    Hi I'm having a problem arriving at the same result in this transmission line question.

    [​IMG]

    Taking Beta = W/U = 2*pi*f/0.7c = (2*pi*2*10^9)/(0.7*2.998*10^-8) = 59.88

    Zo = 100?
    Zin = 92.3 - j67.5

    Zl =
    100 ( 92.3 - j67.5 -j(100)*tan(59.88*0.3) )
    -------------------------------------------
    ( 100 - j(92.3 - j67.5)*tan(59.88*0.3))

    Zl =
    100 ( 92.3 + j54.844 )
    ------------------------
    ( 182.58 + j112.923)

    Zl = 52.41 + j26.328

    So the resistive component is roughly right however the inductive component is pretty far out.


    Can anyone see where I'm going wrong?
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Re-check your calculations - it's just the last step

    Zl = 52.41 + j26.328

    that's wrong.

    Everything is OK up to there.
     
    ECE101 likes this.
  3. ECE101

    Thread Starter New Member

    Nov 25, 2011
    29
    0
    Do'h!

    Serves me right for taking shortcuts with a calculator :rolleyes:

    worked it out by hand and it was fine!

    Thanks t_n_k!
     
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