Wireless and Mobile Device Security, 2nd Edition

Wireless Antennas

Central to the performance of any wireless device is the antenna. There are three main categories of antenna, which are classified by their mode of operation and are used in different circumstances to address specific coverage issues. The three categories are as follows:

• Omnidirectional—These are the general-purpose antennas typically installed by default on WAPs. They radiate radio waves equally in all directions, theoretically providing 360-degree coverage.
• Semi-directional—These antennas are used when coverage is required in a specific direction. Their RF radiance tends to be limited to 180 degrees. These antennas are typically used to radiate RF in one direction.
• Highly directional—These antennas are very specific. They ...