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Transmission Line 'Gamma' Plane

Discussion in 'Radio and Communications' started by rashiidsherif93, Jan 12, 2016.

  1. rashiidsherif93

    rashiidsherif93 New Member

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    Jan 12, 2016
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    Hello all,

    I am trying to tackle a question at University on my Radio frequency module and it is regarding to transmission lines.
    The questions goes like the following:

    Why the magnitude of Г is equal to or less than 1?
    What is the physical meaning of the phase of Г?
    What is the increment of length of a transmission line corresponding to a rotation of 2π of Г ?

    What is the length of the transmission lines having the reflection coefficients Г0 and Г(d) shown below:

    upload_2016-1-12_20-18-11.png

    I understand that with capital gamma ' reflection coefficient' if it is 1 , no power is delivered to the load , if it is 0 full power is delivered to the load. However my theory understanding stops there, could someone clarify these questions for me?

    Thanks in advance
     
    Last edited: Jan 13, 2016
  2. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    Location:
    Richmond Hill , ON Canada near Toronto
    you cannot reflect more power than applied so the worst case reflection = 1 or in log scale 0dB

    The best case is nothing reflected thus a value of 0. (nothing reflected)

    But in practice ,in log scale, -15dB limit may be ok, or more negative for more critical applications.

    When waves have a speed on T line which depends on dielectric constant and speed of light, it produces natural wavelengths, where 1 wavelength is 360deg. A transmission line is said to be harmonic at multiples of 1/2 wavelengths , like a skipping rope or guitar string.

    When odd multiples of a quarter wavelength, impedance is converted in both phase and amplitude. e.g an open cct becomes short and visa versa. are special cases.
     
    Last edited: Jan 17, 2016

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