资 源 简 介
One of the prerequisites for the development of telecommunication services is the
understanding of the propagation of the waves, either acoustic, electromagnetic,
radio or light waves, which are used for the transmission of information.
In this work, we shall limit ourselves to the study of radio waves: this term
apply to the electromagnetic waves used in radio communications. Their
frequency spectrum is very broad, and is divided into the following frequency
bands : ELF waves (f < 3 kHz), VLF (3-30 kHz), LF waves (30-300 kHz), MF
waves (300-3000 kHz), HF (3-30 MHz), VHF waves (30-300 MHz), UHF waves
(300-3000 MHz), SHF waves (3-30 GHz), EHF waves (30-300 GHz) and sub-
EHF waves (300-3000 GHz).
