Deploying License-Free Wireless Wide-Area Networks

Wireless Frequency

As an ocean wave travels, its height changes; as the front of the wave approaches you, the height increases. When the crest passes you, the height of the wave decreases. The height decreases further as the trough passes you. Finally, the height of the sea is back to the level where it was before the wave appeared. You have just experienced one complete up-down-up wave cycle. Without changes in the wave height, there would be no wave cycle or wave.

Changes in the electron flow in an antenna cause the same changes in the electromagnetic fields around the antenna. Another word for electron flow in a wire is current. Without changes in the antenna current, there would be no change in the electromagnetic fields around the antenna; ...