Practical Antenna Handbook 5/e, 5th Edition

CHAPTER 2Radio-Wave Propagation

To intelligently choose the right antenna for our purposes we first need an understanding of how radio waves get from one place to another. Intuitively, radio signal propagation seems similar to light propagation; after all, light and radio signals are both electromagnetic waves. But the propagation of radio signals is not the simple matter that it seems at first glance: Simple inverse square law predictions, based on the optics of visible light, fall down drastically at many radio frequencies because other factors come into play—especially in the vicinity of earth.

In the microwave region of the spectrum, for instance, atmospheric pressure and water vapor content of the air through which a terrestrial electromagnetic ...