Reflection and transmission of signal

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Discussion Overview

The discussion revolves around determining the percentage of a signal that is reflected versus transmitted through a wall, specifically focusing on electromagnetic waves. Participants explore the parameters needed for calculations and the complexities involved in measuring signal behavior in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks a simple method to calculate the reflection and transmission percentages of a signal through a wall, acknowledging the oversimplification of the problem.
  • Another participant suggests that to analyze the signal, properties of the wall such as permittivity, permeability, and conductivity are necessary to calculate the complex impedance, which can then be used to find reflection and transmission coefficients.
  • A different viewpoint highlights that in addition to reflection and transmission, some signal will be absorbed by the wall, questioning the necessity of knowing the reflection percentage specifically.
  • One participant proposes using a field strength meter to measure the signal strength on either side of the wall, noting the variability in wall construction and the challenge of generalizing wall characteristics.
  • Another participant reiterates the need for wall properties to calculate coefficients and requests further explanation or references to papers that provide relevant data.
  • A participant shares links to Wikipedia pages that contain information on reflection and transmission coefficients as potential resources.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and methodology for calculating reflection and transmission percentages, indicating that multiple competing perspectives remain unresolved.

Contextual Notes

Participants note the complexity of wall characteristics and the variability in construction, which may affect the accuracy of general calculations. There is also a mention of using dB for loss factors, which introduces additional considerations for signal measurement.

anarachy
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How do I determine what percentage of a signal is reflected and what percentage goes through a wall.
I know that I am over simplifying things, but for the purpose of my project I need a simple answer to this problem.
What parameters are needed for the solution and how do we calculate this.

Thanks.
 
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What signal are you referring to, the electromagnetic waves? If so, then you need to know some properties of the wall such as permittivity, permeability, and conductivity. You can use that information to calculate the complex impedance of the wall. Then use the complex impedance to calculate the reflection and transmission coefficients.
 
Besides some of the signal passing through the wall and some of the signal reflecting from the wall, some of the signal will also be absorbed by the wall. I can understand the importance of wanting to know how much the wall attenuates the signal but I do not understand why you want to know how much signal is reflected by the wall.

The easiest thing to would be to get a field strength meter and measure how much weaker the signal is on the other side of the wall compared to the same distance without a wall. Walls vary greatly in their construction and it is impossible to generalize about the characteristics of anyone wall. Loss factors in RF are usually expressed in dB instead of percent.
 
what said:
What signal are you referring to, the electromagnetic waves? If so, then you need to know some properties of the wall such as permittivity, permeability, and conductivity. You can use that information to calculate the complex impedance of the wall. Then use the complex impedance to calculate the reflection and transmission coefficients.

Could you may be explain a little further with an example. Or refer a paper which has a table for reflection and transmission coefficients.

Thanks
 

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