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Signal Propagation

  1. Apr 3, 2009 #1
    I read that capability of electromagnetic signal propagation depends on material or conductor from which it is passed...... I want to know How does it effect???..... What are characteristics of conductors that result in attenuation for certain frequencies???
  2. jcsd
  3. Apr 3, 2009 #2
    Thats a very general question. Are you referring to waveguides? If yes, they act as high pass filters: propagation can take place only if the signal frequency exceeds a cutoff frequency decided by the geometry of and dielectric medium inside the guiding structure. As for conductors, they have finite conductivity, so there are losses associated with current flow.

    [EDIT: I am not v. sure if this is the right place to continue this discussion (vs the Electrical Engineering Forum).]
  4. Apr 3, 2009 #3
    Sir I have read that each medium has its bandwidth limitations not regarding heat loss.... so I was asking in such way that Can copper pass THz signals???........If no than why???
  5. Apr 3, 2009 #4
    Because of eddy currents in copper that produce losses and attenuation, ac currents in the copper are forced to the outer surface (see skin effect in reference books). This begins to happen below 1 MHz. By 1 THz the skin depth is very thin.
    Last edited: Apr 3, 2009
  6. Apr 6, 2009 #5
    You could refer to "Field and Wave Electromagnetics" by David Cheng or Engineering Electromagnetics by Nathan Ida, for quantitative explanations.
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