# Positive reflection coefficient

In an article on Wiki, there is a plot that shows a positive reflection coefficient. How is this possible? I can't seem to see how you can get a positive one from this equation alone:

$$\Gamma_= \frac{sin(\theta)-X}{sin(\theta) + X}$$ $$X_{horiz}= \sqrt{\epsilon_c - cos(\theta)^2}$$ $$X_{vert}= \frac{\sqrt{\epsilon_c - cos(\theta)^2}}{\epsilon_c}$$

Image in question:

Article with the image: http://en.wikipedia.org/wiki/2-Ray_Ground_Reflection_Model

I tried plotting it in MATLAB w.r.t theta, and I don't see the plateau, nor do I see the positive reflection coefficients. I'd appreciate some clarification.

• I think you want to look at is as the magnitude of the reflection coefficient being less than or equal to 1. A coefficient of 1 means everything is reflected back if I remember right. -1 means the reflected wave is inverted? This is covered in books on time varying EM fields. – HL-SDK Nov 30 '13 at 2:52