What Is An Antenna?
An antenna is a converter that converts a traveling wave propagating on a transmission line into an electromagnetic wave propagating in an unbounded medium (usually free space), or vice versa. A component used in a radio to transmit or receive electromagnetic waves. Radio communication, radio, television, radar, navigation, electronic warfare, remote sensing, radio astronomy and other engineering systems, all use of electromagnetic waves to transmit information, rely on the antenna to work. In addition, in the use of electromagnetic waves to transmit energy, non-signal energy radiation also need antenna. The general antenna is reversible, that is, the same pair of antennas can be used as both a transmitting antenna and a receiving antenna. The same antenna as the basic characteristics of the launch or reception parameters are the same. This is the reciprocity theorem of the antenna.