Thank you for visiting RF Cafe!

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeView the YouTube RF Cafe Intro VideoKirt Blattenberger
BSEE
KB3UON
EIEIO

Carpe Diem!
(Seize the Day!)

5th MOB:
My USAF radar shop

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse riding website

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
RF & EE Symbols Word
RF Stencils for Visio

Atmospheric Refraction

Due to variations in the density of the atmosphere, electromagnetic radiation is refracted according to the varying refractive index with height. Variations decreases linearly with height under standard conditions (no localized disturbances). As a result, the wave gradually curves until, if the wavelength and angle are correct, the signal bends back toward the earth (see graphic below).

As with visible light waves, radio waves must equal a critical angle in order to be transmitted between regions of different refractive indices. When less than the critical angle is experienced, the waves are bent at the interface back into the medium from which they originate. In the case of an abrupt interface like air and water in a glass, the bending is equally abrupt. Layers of the atmosphere present a much more gradual interface so the reflection tends to exhibit a more curved shape.

Atmospheric refraction of electromagnetic waves vs. frequency - RF Cafe

Pencil refraction in glass of water - RF CafeThis image shows the familiar pencil in a glass of water.

 

 

 

 

Copyright 1996 - 2016
Webmaster:  Kirt Blattenberger, BSEE - KB3UON

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.