Antenna

Antenna, or aerial, component in an electrical circuit that radiates or receives radio waves. A transmitting antenna is a combination of conductors that converts AC electrical energy into electromagnetic radiation. The simple dipole consists of 2 straight conductors energized at the small gap which separates them. It can be made directional by adding electrically isolated director and reflector conductors in front and behind. Other configurations include the folded dipole, the highly directional loop antenna, and the dish type used for microwave links. A receiving antenna can consist merely of a short dielectric rod or a length of wire for low-frequency signals. For VHF and microwave signals, complex antenna configurations similar to those used for transmission must be used.