pattern
System object: phased.CustomAntennaElement
Namespace: phased
Plot custom antenna element directivity and patterns
Syntax
pattern(sElem,FREQ)
pattern(sElem,FREQ,AZ)
pattern(sElem,FREQ,AZ,EL)
pattern(___,Name,Value)
[PAT,AZ_ANG,EL_ANG] = pattern(___)
Description
pattern(
plots
the 3-D array directivity pattern (in dBi) for the element specified
in sElem
,FREQ
)sElem
. The operating frequency is specified
in FREQ
.
pattern(
plots
the element directivity pattern at the specified azimuth angle.sElem
,FREQ
,AZ
)
pattern(
plots
the element directivity pattern at specified azimuth and elevation
angles.sElem
,FREQ
,AZ
,EL
)
pattern(___,
plots the element pattern with additional options specified by one
or more Name,Value
)Name,Value
pair arguments.
returns the element pattern in [PAT,AZ_ANG,EL_ANG]
= pattern(___)PAT
. The AZ_ANG
output
contains the coordinate values corresponding to the rows of PAT
.
The EL_ANG
output contains the coordinate values
corresponding to the columns of PAT
. If the 'CoordinateSystem'
parameter
is set to 'uv'
, then 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.
Note
This method replaces the plotResponse
method.
See Convert plotResponse to pattern for
guidelines on how to use pattern
in place of plotResponse
.
Input Arguments
sElem
— Custom antenna element
System object™
Custom antenna element, specified as a phased.CustomAntennaElement
System object.
Example: sElem = phased.CustomAntennaElement;
FREQ
— Frequency for computing directivity and patterns
positive scalar | 1-by-L real-valued row vector
Frequencies for computing directivity and patterns, specified as a positive scalar or 1-by-L real-valued row vector. Frequency units are in hertz.
For an antenna, microphone, or sonar hydrophone or projector element,
FREQ
must lie within the range of values specified by theFrequencyRange
orFrequencyVector
property of the element. Otherwise, the element produces no response and the directivity is returned as–Inf
. Most elements use theFrequencyRange
property except forphased.CustomAntennaElement
andphased.CustomMicrophoneElement
, which use theFrequencyVector
property.For an array of elements,
FREQ
must lie within the frequency range of the elements that make up the array. Otherwise, the array produces no response and the directivity is returned as–Inf
.
Example: [1e8 2e6]
Data Types: double
AZ
— Azimuth angles
[-180:180]
(default) | 1-by-N real-valued row vector
Azimuth angles for computing directivity and pattern, specified as a 1-by-N real-valued row vector where N is the number of azimuth angles. Angle units are in degrees. Azimuth angles must lie between –180° and 180°.
The azimuth angle is the angle between the x-axis and the projection of the direction vector onto the xy plane. When measured from the x-axis toward the y-axis, this angle is positive.
Example: [-45:2:45]
Data Types: double
EL
— Elevation angles
[-90:90]
(default) | 1-by-M real-valued row vector
Elevation angles for computing directivity and pattern, specified as a 1-by-M real-valued row vector where M is the number of desired elevation directions. Angle units are in degrees. The elevation angle must lie between –90° and 90°.
The elevation angle is the angle between the direction vector and xy-plane. The elevation angle is positive when measured towards the z-axis.
Example: [-75:1:70]
Data Types: double
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
CoordinateSystem
— Plotting coordinate system
'polar'
(default) | 'rectangular'
| 'uv'
Plotting coordinate system of the pattern, specified as the
comma-separated pair consisting of 'CoordinateSystem'
and
one of 'polar'
, 'rectangular'
,
or 'uv'
. When 'CoordinateSystem'
is
set to 'polar'
or 'rectangular'
,
the AZ
and EL
arguments
specify the pattern azimuth and elevation, respectively. AZ
values
must lie between –180° and 180°. EL
values
must lie between –90° and 90°. If 'CoordinateSystem'
is
set to 'uv'
, AZ
and EL
then
specify U and V coordinates,
respectively. AZ
and EL
must
lie between -1 and 1.
Example: 'uv'
Data Types: char
Type
— Displayed pattern type
'directivity'
(default) | 'efield'
| 'power'
| 'powerdb'
Displayed pattern type, specified as the comma-separated pair
consisting of 'Type'
and one of
'directivity'
— directivity pattern measured in dBi.'efield'
— field pattern of the sensor or array. For acoustic sensors, the displayed pattern is for the scalar sound field.'power'
— power pattern of the sensor or array defined as the square of the field pattern.'powerdb'
— power pattern converted to dB.
Example: 'powerdb'
Data Types: char
Normalize
— Display normalize pattern
true
(default) | false
Display normalized pattern, specified as the comma-separated pair consisting of
'Normalize
' and a Boolean. Set this parameter to
true
to display a normalized pattern. This parameter does not
apply when you set 'Type'
to 'directivity'
.
Directivity patterns are already normalized.
Data Types: logical
PlotStyle
— Plotting style
'overlay'
(default) | 'waterfall'
Polarization
— Polarized field component
'combined'
(default) | 'H'
| 'V'
Polarized field component to display, specified as the comma-separated pair consisting of
'Polarization' and 'combined'
, 'H'
, or
'V'
. This parameter applies only when the sensors are
polarization-capable and when the 'Type'
parameter is not set to
'directivity'
. This table shows the meaning of the display
options.
'Polarization' | Display |
---|---|
'combined' | Combined H and V polarization components |
'H' | H polarization component |
'V' | V polarization component |
Example: 'V'
Data Types: char
Output Arguments
PAT
— Element pattern
N-by-M real-valued matrix
Examples
Power and Directivity Patterns of Custom Antenna
Create a custom antenna with a cosine pattern. Show the response at boresight. Then, plot the antenna's field and directivity patterns.
Create the antenna and calculate the response. The user-defined pattern is omnidirectional in the azimuth direction and has a cosine pattern in the elevation direction. Assume the antenna works at 1 GHz.
fc = 1e9;
antenna = phased.CustomAntennaElement;
antenna.AzimuthAngles = -180:180;
antenna.ElevationAngles = -90:90;
antenna.MagnitudePattern = mag2db(repmat(cosd(antenna.ElevationAngles)', ...
1,numel(antenna.AzimuthAngles)));
resp = antenna(fc,[0;0])
resp = 1
Plot an elevation cut of the magnitude response as a line plot.
pattern(antenna,fc,0,[-90:90],'CoordinateSystem','rectangular', ... 'Type','efield')
Plot an elevation cut of the directivity as a line plot, showing that the maximum directivity is approximately 2 dB.
pattern(antenna,fc,0,[-90:90],'CoordinateSystem','rectangular', ... 'Type','directivity')
Pattern of Custom Antenna over Selected Range of Angles
Create a custom antenna System object™. The user-defined pattern is omnidirectional in the azimuth direction and has a cosine pattern in the elevation direction. Assume the antenna operates at a frequency of 1 GHz. First show the response at boresight. Display the 3-D pattern for a 60 degree range of azimuth and elevation angles centered at 0 degrees azimuth and 0 degrees elevation in 0.1 degree increments.
fc = 1e9; azang = -180:180; elang = -90:90; magpattern = mag2db(repmat(cosd(elang)',1,numel(azang))); antenna = phased.CustomAntennaElement('AzimuthAngles',azang, ... 'ElevationAngles',elang,'MagnitudePattern',magpattern); resp = antenna(fc,[0;0])
resp = 1
Plot the power pattern for a range of angles.
pattern(antenna,fc,[-30:0.1:30],[-30:0.1:30],'CoordinateSystem','polar', ... 'Type','power')
More About
Directivity
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.
Convert plotResponse to pattern
For antenna, microphone, and array System objects, the pattern
method
replaces the plotResponse
method. In addition, two new simplified
methods exist just to draw 2-D azimuth and elevation pattern plots. These methods are
patternAzimuth
and patternElevation
.
The following table is a guide for converting your code from
using plotResponse
to pattern
.
Notice that some of the inputs have changed from input arguments to Name-Value pairs
and conversely. The general pattern
method syntax
is
pattern(H,FREQ,AZ,EL,'Name1','Value1',...,'NameN','ValueN')
plotResponse Inputs | plotResponse Description | pattern Inputs | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
H argument | Antenna, microphone, or array System object. | H argument (no change) | ||||||||||||||||||||
FREQ argument | Operating frequency. | FREQ argument (no change) | ||||||||||||||||||||
V argument | Propagation speed. This argument is used only for arrays. | 'PropagationSpeed' name-value pair. This
parameter is only used for arrays. | ||||||||||||||||||||
'Format' and 'RespCut' name-value
pairs | 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 | ||||||||||||||||||||
'CutAngle' name-value pair | Constant angle at to take an azimuth or elevation cut. When
producing a 2-D plot and when 'RespCut' is set
to 'Az' or 'El' , use 'CutAngle' to
set the slice across which to view the plot. | No equivalent name-value pair. To create a cut, specify either AZ or EL as
a scalar, not a vector. | ||||||||||||||||||||
'NormalizeResponse' name-value pair | Normalizes the plot. When 'Unit' is set
to 'dbi' , you cannot specify 'NormalizeResponse' . | Use the | ||||||||||||||||||||
'OverlayFreq' name-value pair | Plot multiple frequencies on the same 2-D plot. Available only
when 'Format' is set to 'line' or 'uv' and 'RespCut' is
not set to '3D' . The value true produces
an overlay plot and the value false produces a
waterfall plot. |
The values | ||||||||||||||||||||
'Polarization' name-value pair | Determines how to plot polarized fields. Options are 'None' , 'Combined' , 'H' ,
or 'V' . | 'Polarization' name-value pair determines
how to plot polarized fields. The 'None' option
is removed. The options 'Combined' , 'H' ,
or 'V' are unchanged. | ||||||||||||||||||||
'Unit' name-value pair | Determines the plot units. Choose 'db' , 'mag' , 'pow' ,
or 'dbi' , where the default is 'db' . |
| ||||||||||||||||||||
'Weights' name-value pair | Array element tapers (or weights). | 'Weights' name-value pair (no change). | ||||||||||||||||||||
'AzimuthAngles' name-value pair | Azimuth angles used to display the antenna or array response. |
| ||||||||||||||||||||
'ElevationAngles' name-value pair | Elevation angles used to display the antenna or array response. |
| ||||||||||||||||||||
'UGrid' name-value pair | Contains U coordinates in UV-space. |
| ||||||||||||||||||||
'VGrid' name-value pair | Contains V-coordinates in UV-space. |
|
Version History
Introduced in R2015a
See Also
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