dipole antenna

Thân thiện

A technician adjusts a dipole antenna on a rooftop.

Definition

1. Noun:
   • A type of radio antenna: A "dipole antenna" is a fundamental and common type of antenna used for transmitting or receiving radio signals. It consists of two identical conductive elements, such as metal rods or wires, arranged in a straight line and driven by a radio frequency signal from a transmission line connected at their center.

Usage

• The term "dipole antenna" is used to describe a specific antenna structure in the fields of telecommunications, radio, and electronics. It is often discussed in technical contexts related to signal transmission, reception, and antenna theory.

Examples

• Noun:
  • The simplest form of a dipole antenna is a half-wavelength dipole.
  • For our amateur radio setup, we installed a basic dipole antenna between two trees.
  • The textbook explains how the radiation pattern of a dipole antenna is calculated.

Advanced Usage

• "Half-wave dipole": The most common and fundamental type of dipole antenna, with each conductive element being approximately one-quarter of the wavelength of the operating frequency, making the total length about half a wavelength.

  • The impedance of a half-wave dipole in free space is approximately 73 ohms.

• "Folded dipole": A variation where the two conductive elements are folded back on themselves, offering different impedance characteristics.

  • A folded dipole antenna is often used in television reception due to its wider bandwidth.

Variants and Related Words

• Dipole (noun): Often used as a shortened, informal term for "dipole antenna."

  • The signal strength improved after we adjusted the dipole.

• Antenna (noun): The general category of devices for transmitting or receiving electromagnetic waves, of which a dipole is one type.

Synonyms

• Doublet: A less common synonym, especially in older technical literature.
• Hertzian dipole: A theoretical model of an infinitesimally small dipole used for fundamental electromagnetic calculations.

Related Phrases

• Dipole moment: A related but distinct concept in physics describing the separation of positive and negative charges in a system. (Note: This is a related scientific term, not a phrasal verb of "dipole antenna").

Notes

• The "dipole antenna" is a foundational concept in antenna design. Its operation is based on creating an oscillating electric dipole, which radiates electromagnetic waves. The length of its elements is directly related to the wavelength (and thus frequency) of the signal it is designed for.

Học thuật

Noun

1. an aerial half a wavelength long consisting of two rods connected to a transmission line at the center

Từ đồng nghĩa

• dipole