Electromagnetics: Plane Wave Propagation, Unknown Medium

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Captain1024
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Homework Statement


Based on wave attenuation and reflection measurements conducted at 1MHz, it was determined that the intrinsic impedance of a certain medium is
gif.latex?28.1%5Cangle%2045%5E%5Ccirc%20%5C%20%28%5COmega%29.gif
, and the skin depth is 2m.
Determine:
a) The conductivity of the medium
b) The wavelength in the medium
c) The phase velocity.

Answer to a) 2.52x10^-2 S/m

Homework Equations


N/A

The Attempt at a Solution


I need to know what type of medium this wave is traveling through. We learned five types in class: Perfect Dielectric, Low-Loss Dielectric, Quasi-Conductor, Good Conductor, Perfect Conductor. The way I learned to determine the type of medium was by using a ratio of
gif.latex?%5Cfrac%7B%5Cepsilon%27%27%7D%7B%5Cepsilon%27%7D.gif
. Where
gif.latex?%5Cepsilon%27%27%20%3D%20%5Cfrac%7B%5Csigma%7D%7B%5Comega%7D.gif
, and
gif.latex?%5Cepsilon%27%20%3D%20%5Cepsilon.gif
. How can I determine this ratio if one of the terms in the ratio is unknown (namely, the conductivity ##\sigma##)? The angle ##45^\circ## was mentioned in class when we were talking about good conductors. And, the phase angle of the intrinsic impedance is ##45^\circ##. But, is there a method for determining medium type using phase angle of the intrinsic impedance?

-Captain1024
 
Last edited by a moderator:
Captain1024 said:

Homework Statement


Based on wave attenuation and reflection measurements conducted at 1MHz, it was determined that the intrinsic impedance of a certain medium is
gif.latex?28.1%5Cangle%2045%5E%5Ccirc%20%5C%20%28%5COmega%29.gif
, and the skin depth is 2m.
Determine:
a) The conductivity of the medium
b) The wavelength in the medium
c) The phase velocity.

Answer to a) 2.52x10^-2 S/m

Homework Equations


N/A

The Attempt at a Solution


I need to know what type of medium this wave is traveling through. We learned five types in class: Perfect Dielectric, Low-Loss Dielectric, Quasi-Conductor, Good Conductor, Perfect Conductor. The way I learned to determine the type of medium was by using a ratio of
gif.latex?%5Cfrac%7B%5Cepsilon%27%27%7D%7B%5Cepsilon%27%7D.gif
. Where
gif.latex?%5Cepsilon%27%27%20%3D%20%5Cfrac%7B%5Csigma%7D%7B%5Comega%7D.gif
, and
gif.latex?%5Cepsilon%27%20%3D%20%5Cepsilon.gif
. How can I determine this ratio if one of the terms in the ratio is unknown (namely, the conductivity ##\sigma##)? The angle ##45^\circ## was mentioned in class when we were talking about good conductors. And, the phase angle of the intrinsic impedance is ##45^\circ##. But, is there a method for determining medium type using phase angle of the intrinsic impedance?

-Captain1024
If and only if conductivity is zero, the intrinsic impedance η is real. There is a formula relating η to μ, ε, ω and conductivity γ. Here η has real and imaginary parts.
There is another formula relating skin depth δ to ω, μ and γ. δ also has real and imaginary parts here.
From the given data (ω and the real and imaginary parts of η) you can answer the question.
 
Last edited: