The antennas are characterized by a number of parameters. Radiation pattern is a graphic representation of radiation characteristics of an antenna according to direction (azimuth and elevation coordinates). Most often represent the radiated power density, but also can find diagrams or phase bias (military antennas). Considering the radiative pattern, we can make a general classification of types of antenna and we can define the directivity of a receiver (isotropic antenna, directional, bi-directional, omni).
This parameter is defined as the ratio between the maximum radiated power in a geometric direction and power radiated in opposite direction. When this relationship is reflected in dB scale, the ratio F / B (Front / Back) is the difference in dB between the maximum radiation level and radiation level of 180 degrees. This parameter is especially useful when interference back is critical in choosing the antenna that we use.
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.
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.
This parameter is defined as the ratio between the maximum radiated power in a geometric direction and power radiated in opposite direction. When this relationship is reflected in dB scale, the ratio F / B (Front / Back) is the difference in dB between the maximum radiation level and radiation level of 180 degrees. This parameter is especially useful when interference back is critical in choosing the antenna that we use.
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.
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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