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Pattern

Far area radiated electromagnetic field of antenna
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The pattern is the far area radiation of the antenna electromagnetic field It can be expressed as E θ= E0[e ˙ (-jkr)/r]f( θ,φ)。
Chinese name
Pattern
Alias
far field Pattern
expression
E θ= E0[e ˙ (-jkr)/r]f( θ,φ)
Applicable fields
electric field intensity
Applied discipline
Directional function

Directional function

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Generally,
H φ= E θ/η zero
Where E θ yes electric field intensity θ Component of, unit: V/m; H φ Is magnetic field strength degree φ Component of, unit: A/m; E is the coefficient related to incentive; f( θ,φ) Called antenna directional function η 0=√( μ 0/ ε 0)=120 π is free space Wave impedance k=2π/ λ Is the propagation constant. Therefore, the radiation field strength E of the antenna is available on the sphere away from the antenna r directional function f( θ,φ) express. Use its maximum value fmax normalization Later referred to as normalization directional function , marked as F( θ,φ)。 Directional function includes amplitude directional function phase Directional function and power density Directional function. Generally, little attention is paid to the phase distribution, so unless otherwise specified, normalization Directional functions refer to normalized amplitude directional functions.
normalization Amplitude directivity function F( θ,φ)=| E( θ,φ)|/| E( θ,φ)| max=f( θ,φ)/ fmax
normalization Power directivity function S( θ,φ)= F( θ,φ)* F( θ,φ)
Traditionally, the directional function is expressed in decibels FdB=20lg [F( θ,φ)] dB

Changing relationship

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The pattern is a graphical representation of directivity function, which can graphically describe the relationship between antenna radiation characteristics and spatial directional coordinates. Radiation characteristics include radiation intensity field strength , phase and polarization. Usually discussed in far field radius The antenna radiation (or reception) power Or the change rule of field intensity with the coordinate of position direction, which is called power pattern and field pattern respectively. The antenna pattern is shown in far field So it is also called far-field pattern.
directional function The directional map drawn is called normalization The pattern is represented by dimensionless relative values or decibels. There are 2D and 3D directional maps. 3D directional map is divided into spherical coordinate 3D directional map and Cartesian coordinates 3D pattern, 2D pattern is divided into polar coordinates There are two kinds of pattern and rectangular coordinate pattern.
An antenna radiation pattern or antenna pattern is difined as "a mathematical function or graphical representation of the radiation properties of the antenna as a function of space coordinate."
2D rectangular coordinate pattern
2D polar coordinate pattern
3D pattern
3D pattern