Plot antenna or transducer element directivity and patterns
[PAT,AZ_ANG,EL_ANG] = pattern(___)
pattern(___, plots the
element pattern with additional options specified by one or more
returns the element pattern in
EL_ANG] = pattern(___)
contains the coordinate values corresponding to the rows of
EL_ANG output contains the coordinate values corresponding to the columns
PAT. If the
'CoordinateSystem' parameter is set to
AZ_ANG contains the U
coordinates of the pattern and
EL_ANG contains the V
coordinates of the pattern. Otherwise, they are in angular units in degrees.
UV units are dimensionless.
element— Antenna or transducer element
Antenna or transducer element, specified as a Phased Array System Toolbox System object.
comma-separated pairs of
the argument name and
Value is the corresponding value.
Name must appear inside quotes. You can specify several name and value
pair arguments in any order as
'Polarization'— Polarization type
Polarization type, specified as the comma-separated pair consisting of
'Polarization' and either
'combined', the horizontal and vertical polarization patterns are
'H', only the horizontal
polarization is displayed. If
only the vertical polarization is displayed.
To enable this property, set the
element argument to an antenna
that supports polarization:
phased.CustomAntennaElement, and then set the
name-value pair to
Directivity describes the directionality of the radiation pattern of a sensor element or array of sensor elements.
Higher directivity is desired when you want to transmit more radiation in a specific direction. Directivity is the ratio of the transmitted radiant intensity in a specified direction to the radiant intensity transmitted by an isotropic radiator with the same total transmitted power
where Urad(θ,φ) is the radiant intensity of a transmitter in the direction (θ,φ) and Ptotal is the total power transmitted by an isotropic radiator. For a receiving element or array, directivity measures the sensitivity toward radiation arriving from a specific direction. The principle of reciprocity shows that the directivity of an element or array used for reception equals the directivity of the same element or array used for transmission. When converted to decibels, the directivity is denoted as dBi. For information on directivity, read the notes on Element directivity and Array directivity.
Computing directivity requires integrating the far-field transmitted radiant intensity over all directions in space to obtain the total transmitted power. There is a difference between how that integration is performed when Antenna Toolbox™ antennas are used in a phased array and when Phased Array System Toolbox antennas are used. When an array contains Antenna Toolbox antennas, the directivity computation is performed using a triangular mesh created from 500 regularly spaced points over a sphere. For Phased Array System Toolbox antennas, the integration uses a uniform rectangular mesh of points spaced 1° apart in azimuth and elevation over a sphere. There may be significant differences in computed directivity, especially for large arrays.
The azimuth angle of a vector is the angle between the x-axis and its orthogonal projection onto the xy-plane. The angle is positive when going from the x-axis toward the y-axis. Azimuth angles lie between –180° and 180° degrees, inclusive. The elevation angle is the angle between the vector and its orthogonal projection onto the xy-plane. The angle is positive when going toward the positive z-axis from the xy-plane. Elevation angles lie between –90° and 90° degrees, inclusive.
For antenna, transducer, and array System objects, the
pattern function replaces the
In addition, two new simplified functions exist just to draw 2-D azimuth and elevation pattern
plots. These functions are
The following table is a guide for converting your code from using
pattern. Notice that some of the
inputs have changed from input arguments to Name-Value
pairs and conversely. The general
pattern method syntax
|plotResponse Inputs||plotResponse Description||pattern Inputs|
|Antenna, microphone, or array System object.|
|Propagation speed. This argument is used only for arrays.|
These options work together to let you create a plot
in angle space (line or polar style) or UV space.
They also determine whether the plot is 2-D or 3-D. This table shows
you how to create different types of plots using
If you set
|Constant angle at to take an azimuth or elevation cut. When
producing a 2-D plot and when ||No equivalent name-value pair. To create a cut, specify either |
|Normalizes the plot. When |
you cannot specify
|Plot multiple frequencies on the same 2-D plot. Available only
|Determines how to plot polarized fields. Options are |
|Determines the plot units. Choose |
|Array element tapers (or weights).|
|Azimuth angles used to display the antenna or array response.|
|Elevation angles used to display the antenna or array response.|
|Contains U coordinates in UV-space.|
|Contains V-coordinates in UV-space.|