# Reflection and transmission of signal

1. Jul 23, 2011

### anarachy

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.

2. Jul 23, 2011

### waht

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.

3. Jul 23, 2011

### skeptic2

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 any one wall. Loss factors in RF are usually expressed in dB instead of percent.

4. Jul 25, 2011

### anarachy

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

5. Jul 25, 2011