How Do I Determine the Best Antenna Length?
Dipole antenna (English: Dipole antenna or doublet) is the earliest, simplest and most widely used antenna in radio communications. It consists of a pair of symmetrically placed conductors, and the two ends of the conductors that are close to each other are respectively connected to the feeder. When used as a transmitting antenna, an electrical signal is fed into the conductor from the center of the antenna; when used as a receiving antenna, the received signal is also obtained from the conductor at the center of the antenna. Common dipole antennas consist of two coaxial, straight wires. The radiation field generated by such antennas in the distance is axisymmetric and can be strictly solved theoretically. A dipole antenna is a resonant antenna. Theoretical analysis shows that the current distribution in a slender dipole antenna has the form of a standing wave. The wavelength of the standing wave is exactly the wavelength of the electromagnetic wave generated or received by the antenna. Therefore, when making a dipole antenna, the length of the antenna is determined by the operating wavelength. The most common dipole antenna is a half-wave antenna, whose total length is approximately half of the operating wavelength. In addition to half-wave antennas composed of straight wires, other types of dipole antennas are sometimes used, such as full-wave antennas, short antennas formed by straight wires, and more complex cage antennas and bat-wing antennas. Historically, the antenna used by Heinrich Hertz in experiments to verify the existence of electromagnetic waves is a dipole antenna.
- Dipole antenna (English: Dipole antenna or doublet)
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- An antenna is a device used to transmit or receive radio waves, and is broadly an electronic component of electromagnetic waves. Antennas are used in radio and television, point-to-point radio communications, radar and space exploration systems. Antennas usually work in air and outer space, can also operate underwater, and even work in soil and rock at certain frequencies.
- Physically speaking, an antenna is a combination of one or more conductors, which can generate an radiated electromagnetic field due to the applied time-varying voltage or time-varying current, or it can be placed in an electromagnetic field, due to field induction A time-varying current is generated inside the antenna and a time-varying voltage is generated at its terminals. [1]