# Building Materials Refractive Index?

1. Jun 22, 2009

### whitenight541

Building Materials Refractive Index??

Hi all,

does anybody know the refractive indices of these materials (used in houses)?
- Wall bricks
- Wood (used in doors)
- Glass
- Plastic
- Concrete (in ceiling and floor)

and any other common materials :)

2. Jun 22, 2009

### mgb_phys

Re: Building Materials Refractive Index??

At what wavelength?
The refractive index of something that isn't transparent isn't much use

3. Jun 22, 2009

### whitenight541

Re: Building Materials Refractive Index??

I want it to model transmission of electro-magnetic waves (not light) ..

at microwave frequency 2.4 GHz

If it is possible I want the absolute refractive index

thanks

4. Jun 22, 2009

### mgb_phys

Re: Building Materials Refractive Index??

Google shows up a bunch of papers for microwave and Ka band frequency
In practice the wavelength is similair to the thickness of building materials in a wall so modelling it might be trickier - I would imagine it's also very dependant on water content of something like brick/concrete

5. Jun 22, 2009

### Bob S

Re: Building Materials Refractive Index??

The index of refraction (= sqrt(dielectric constant)) in materials is a complex number, meaning that it has both refraction properties (like glass) and attenuation properties (like opaqueness). It is the attenuation property that reduces the transmission of microwaves.
Propagator = ejωt-γz where γ is complex: γ = +/-sqrt(σμjω-εμω2)
The ratio of attenuation to dielectric constant is called the loss tangent.
tan(δ) = σ/εω. So attenuation is proportional to
e-sqrt(σμω)z
See
http://en.wikipedia.org/wiki/Loss_tangent

α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω

6. Jun 22, 2009

### Andy Resnick

Re: Building Materials Refractive Index??

There's a lot of available data online and elsewhere, for example:

7. Jun 22, 2009

### Bob S

Last edited by a moderator: Apr 24, 2017
8. Jun 23, 2009

### whitenight541

Re: Building Materials Refractive Index??

I don't have a springerlink account .. I would be so grateful if you just posted the refractive indices :)