Electromagnetics: Plane Wave Propagation, Unknown Medium

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SUMMARY

The discussion focuses on determining the properties of an unknown medium through which a plane wave propagates at 1MHz. Key findings include the calculated conductivity of the medium at 2.52x10^-2 S/m, along with the need to analyze the intrinsic impedance and skin depth to classify the medium type. The phase angle of the intrinsic impedance, noted as 45°, is crucial for identifying whether the medium is a good conductor or another type. The relationship between intrinsic impedance, skin depth, and conductivity is emphasized as essential for solving the problem.

PREREQUISITES
  • Understanding of intrinsic impedance and its components
  • Knowledge of skin depth calculations in electromagnetics
  • Familiarity with wave propagation in different types of media
  • Basic principles of electromagnetic theory, including phase angles
NEXT STEPS
  • Research the relationship between intrinsic impedance and conductivity in electromagnetic theory
  • Study the formulas for calculating skin depth in various media
  • Explore the classification of media types based on electromagnetic properties
  • Learn about the implications of phase angles in wave propagation
USEFUL FOR

Students and professionals in electrical engineering, particularly those focusing on electromagnetics, wave propagation, and material characterization in various media.

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:

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