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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.
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.
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).
You can also define the beam width between zero, which is the angular range of the main beam of a radiation pattern between two adjacent zeros to maximum. Create antennas radiated electromagnetic fields. Polarized electromagnetic defined in a certain direction, as the geometric shape that traces the edge of electric field vector at a certain distance from the antenna, to change the time.
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.
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.
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).
You can also define the beam width between zero, which is the angular range of the main beam of a radiation pattern between two adjacent zeros to maximum. Create antennas radiated electromagnetic fields. Polarized electromagnetic defined in a certain direction, as the geometric shape that traces the edge of electric field vector at a certain distance from the antenna, to change the time.
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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