I'm trying to understand the characteristics of RF signals/waves in different environments. I am wondering if there is any data out there regarding how much a wireless signal reflect from an object or get absorbed by it.
Would this be tabulated under common items such as metals, wood, and concrete? (I'm less concerned with water) I'm mainly interested in 2.45 Ghz, but it might be interesting to look at other frequencies.
If no one knows of a tabulated form, here is the alternative question:
What causes RF waves to reflect or absorb? Does the reflective/absorptive property of RF waves act similarly to light properties? Are permittivity and permeability in electromagnetism causing the reflection/absorption? If yes to the last question, could you elaborate how it is (since Wikipedia only describes when the object is the medium forming the waves, not as the receiver)?
Best Answer
If the material is perfectly conductive you get a reflection which follows snells law. If the material is not conductive you get some of the wave that does not get reflected and enters the material, at which point it probably get attenuated.
Source: Antennas
Take for example a wall, the boundary between the air and the wall causes a reflection, and some of the wave enters the material of the wall. The wall has an impedance, which means some of the wave will also get absorbed (ohmic losses, not shown in the equations below). And then more relfection on the way out.
Usually we use seperate equations in optics and in electromagnetics, because of the difficulty of working with these equations. Usually ohmic losses in RF are from
As your questions stand they are probably too broad for the scope of this site, however, I took a crack at answering them anyway. If your really interested in this, then pick up any Electromagnetics Theory book.