The purpose of this chapter is to familiarize the reader with the basic propagation

characteristics that describe various wireless communication channels, such as

terrestrial, atmospheric, and ionospheric for VHF to the X-band. Well-known

standards in wireless communication [1–10] are introduced for the prediction of path

losses and fading effects of any radio signal in various communication links, and

finally, new possibilities that can be obtained using smart antennas are discussed