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).
Within the transmission we can define co-polar diagram that represents the communication from to a desired polarity and polarized radiation pattern with the opposite polarity to that you already have. The most important parameters of the radiation pattern are: pointing direction: The maximum radiation. Directivity and Gain. Main lobe constitutes angular range around the direction of maximum radiation. Side lobes are other relative maxima, lower the principal value.
This relationship also can be seen from another point of view, indicating how good the antenna in the rejection of signals from the rear. Rarely is really important, because the interference from the rear do not usually happen, but it can happen. The F / B ratio is not a very useful number because often varies greatly from one channel to another. Of course, if it is the radiation pattern, then the F / B is not needed.
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.
A transmitter with more than about 3 items are usually less sensitive in a circle slice perpendicular towards the main direction of a jet and therefore one can put antennas in close proximity to a base station. The distance between the antennas should be at least 1 / 2-1 of main wavelengths used. Further away than about 10 wavelengths (far field) affects largely the antenna radiation pattern, but it can affect radio propagation or radio broadcast.
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.
Within the transmission we can define co-polar diagram that represents the communication from to a desired polarity and polarized radiation pattern with the opposite polarity to that you already have. The most important parameters of the radiation pattern are: pointing direction: The maximum radiation. Directivity and Gain. Main lobe constitutes angular range around the direction of maximum radiation. Side lobes are other relative maxima, lower the principal value.
This relationship also can be seen from another point of view, indicating how good the antenna in the rejection of signals from the rear. Rarely is really important, because the interference from the rear do not usually happen, but it can happen. The F / B ratio is not a very useful number because often varies greatly from one channel to another. Of course, if it is the radiation pattern, then the F / B is not needed.
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.
A transmitter with more than about 3 items are usually less sensitive in a circle slice perpendicular towards the main direction of a jet and therefore one can put antennas in close proximity to a base station. The distance between the antennas should be at least 1 / 2-1 of main wavelengths used. Further away than about 10 wavelengths (far field) affects largely the antenna radiation pattern, but it can affect radio propagation or radio broadcast.
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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