A radio antenna (or just aerial) is a transducer that can send and receive radio waves (electromagnetic waves) designed for radio, TV, cell phones, radar or satellite. A radio antenna is a transducer with a usable efficiency can perform one or both of these energy conversions: marketable alternating electrical energy for transmission of radio wave energy. Marketable radio wave energy to alternating electrical energy (military antennas).
Most radio aerials today is primarily designed to be able to send or receive radio waves in a narrow frequency band, for example. FM via VHF band II (87.5-108 MHz). Masts propagate / receives radio waves through coupling with the alternating magnetic field. These types of antenna are used for long-wave, medium-wave and short-wave up to about 6MHz. It is possible to realize antennas that operate according to this principle, up to 60 MHz.
Beamwidth: The angular range of directions in which the radiation of a beam takes a value 3 dB below the maximum. The direction in which the radiated power is halved. Ratio at the secondary main lobe (SLL): The ratio in dB between the maximum value of main lobe and the maximum value of secondary lobe. Front-back ratio (FBR): The ratio in dB between the value of maximum radiation and the same direction and opposite direction.
Bandwidth is a frequency range in which the antenna parameters meet certain characteristics. Can define impedance bandwidth, polarization, gain or other parameters. Directivity is the impedance of masts at its terminals. It is the relationship between the voltage and the input current. Z = frac V I. The impedance is a complex number. The real part of an impedance is called mast resistance and the imaginary part is reactance.
The antenna resistance is the sum of the transmission resistance and loss resistance. The antennas are called resonant when its input reactance vanishes. Beam is a radiation parameter, linked to a radiation pattern. May define the beam width at -3 dB, which is angular range within which the radiated power density is equal to half of maximum power (in main direction of radiation).
There are three basic types of transmitters: wire, aperture and planar antennas. Also, clusters of these aerials (arrays) are usually considered in the literature as another basic type of antenna. Wire transmitters are variants whose radiating elements are wire conductors having a negligible section relative to wavelength employment.
The polarization can be linear, circular and elliptical. Linear polarization can take different orientations (horizontal, vertical, +45, -45). The circular or elliptical polarizations can be right or left (right-handed or left-handed), according to the direction of rotation of the field (observed away from the antenna). Transmitters within decoupling coefficient defined polarization. This measures the amount of power that is capable of receiving a polarized antenna of a form having an effective.
The wire transmitters are analyzed from the electrical currents of the conductors. Aperture aerials are those that use surfaces or openings to direct the electromagnetic beam which concentrate their transmission and reception antenna system in one direction.
Most radio aerials today is primarily designed to be able to send or receive radio waves in a narrow frequency band, for example. FM via VHF band II (87.5-108 MHz). Masts propagate / receives radio waves through coupling with the alternating magnetic field. These types of antenna are used for long-wave, medium-wave and short-wave up to about 6MHz. It is possible to realize antennas that operate according to this principle, up to 60 MHz.
Beamwidth: The angular range of directions in which the radiation of a beam takes a value 3 dB below the maximum. The direction in which the radiated power is halved. Ratio at the secondary main lobe (SLL): The ratio in dB between the maximum value of main lobe and the maximum value of secondary lobe. Front-back ratio (FBR): The ratio in dB between the value of maximum radiation and the same direction and opposite direction.
Bandwidth is a frequency range in which the antenna parameters meet certain characteristics. Can define impedance bandwidth, polarization, gain or other parameters. Directivity is the impedance of masts at its terminals. It is the relationship between the voltage and the input current. Z = frac V I. The impedance is a complex number. The real part of an impedance is called mast resistance and the imaginary part is reactance.
The antenna resistance is the sum of the transmission resistance and loss resistance. The antennas are called resonant when its input reactance vanishes. Beam is a radiation parameter, linked to a radiation pattern. May define the beam width at -3 dB, which is angular range within which the radiated power density is equal to half of maximum power (in main direction of radiation).
There are three basic types of transmitters: wire, aperture and planar antennas. Also, clusters of these aerials (arrays) are usually considered in the literature as another basic type of antenna. Wire transmitters are variants whose radiating elements are wire conductors having a negligible section relative to wavelength employment.
The polarization can be linear, circular and elliptical. Linear polarization can take different orientations (horizontal, vertical, +45, -45). The circular or elliptical polarizations can be right or left (right-handed or left-handed), according to the direction of rotation of the field (observed away from the antenna). Transmitters within decoupling coefficient defined polarization. This measures the amount of power that is capable of receiving a polarized antenna of a form having an effective.
The wire transmitters are analyzed from the electrical currents of the conductors. Aperture aerials are those that use surfaces or openings to direct the electromagnetic beam which concentrate their transmission and reception antenna system in one direction.
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