BASIC ANTENNAS FOR COMMUNICATION SYSTEMS

Summary

Antennas are major component in communication systems. An antenna is used to radiate efficiently electromagnetic energy in desired directions. Antennas match radio‐frequency systems, sources of electromagnetic energy, to space. Antennas are used in systems such as radio and television broadcasting, point‐to‐point radio communication, wireless LAN, cell phones, radar, medical systems, and spacecraft communication. Dipole antenna consists of two straight conductors excited by a voltage fed via a transmission line. Reflector and horn antennas are defined as aperture antennas. The longest dimension of an aperture antenna is higher than several wavelengths. Horn antennas are used as a feed element for radio astronomy, satellite tracking and communication reflector antennas, and as phased arrays radiating elements used in antenna calibration and measurements. In antenna arrays, electromagnetic wave interference is used to enhance electromagnetic signal in one desired direction at the expense of other directions.