Ionospheric reflection is a bending, through a complex process involving reflection and refraction, of electromagnetic waves propagating in the ionosphere back toward the Earth.
The amount of bending depends on the extent of penetration (which is a function of frequency), the angle of incidence, polarization of the wave, and ionospheric conditions, such as the ionization density. It is negatively affected by incidents of ionospheric absorption.
This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C".