Cosine antenna element
CosineAntennaElement object models an antenna with a
cosine response in both azimuth and
elevation. The main response axis (MRA) points to 0° azimuth and 0° elevation in the antenna
coordinate system. When placed in a linear array, the MRA is normal to the array axis (see,
phased.ULA). When placed in a planar array, the MRA
points along the array normal (see, for example,
To compute the response of the antenna element for specified directions:
phased.CosineAntennaElementobject and set its properties.
Call the object with arguments, as if it were a function.
To learn more about how System objects work, see What Are System Objects?
This antenna element does not support polarization.
creates a cosine antenna System object™,
antenna = phased.CosineAntennaElement
antenna. This object models an antenna element whose
response is a cosine function raised to nonnegative powers in the azimuth and elevation
creates a cosine antenna object,
antenna = phased.CosineAntennaElement(
antenna, with each specified
property set to the specified value. You can specify additional name-value pair arguments
in any order as
Unless otherwise indicated, properties are nontunable, which means you cannot change their
values after calling the object. Objects lock when you call them, and the
release function unlocks them.
If a property is tunable, you can change its value at any time.
For more information on changing property values, see System Design in MATLAB Using System Objects.
FrequencyRange — Operating frequency range
[0 1e20] (default) | nonnegative, real-valued 1-by-2 row vector
Operating frequency range of the antenna, specified as a nonnegative, real-valued, 1-by-2 row
vector in the form
[LowerBound HigherBound]. The antenna
element has no response outside the specified frequency range. Units are in
CosinePower — Exponent of cosine pattern
[1.5 1.5] (default) | non-negative scalar | non-negative, real-valued, 1-by-2 vector
Exponents of the cosine pattern, specified as a non-negative scalar or a
non-negative, real-valued, 1-by-2 vector. Exponent values must be real numbers greater
than or equal to zero. When you set
CosinePower to a scalar, both
the azimuth direction cosine pattern and the elevation direction cosine pattern are
raised to the same power. When you set
CosinePower to a 1-by-2
vector, the first element is the exponent for the azimuth direction cosine pattern. The
second element is the exponent for the elevation direction cosine pattern.
The object performs an initialization the first time the object is executed. This
initialization locks nontunable properties
and input specifications, such as dimensions, complexity, and data type of the input data.
If you change a nontunable property or an input specification, the System object issues an error. To change nontunable properties or inputs, you must first
release method to unlock the object.
FREQ — Operating frequency of antenna element
nonnegative scalar | nonnegative, real-valued 1-by-L row vector
Operating frequency of the antenna element, specified as a nonnegative scalar or nonnegative, real-valued 1-by-L row vector. Frequency units are in Hz.
FREQ must lie within the range of values specified by the
FrequencyRange or the
property of the element. Otherwise, the element produces no response and the response is
–Inf. Element objects use the
FrequencyRange property, except for
phased.CustomAntennaElement, which uses the
RESP — Voltage response of antenna
complex-valued M-by-L matrix
Voltage response of antenna element, returned as a complex-valued
M-by-L matrix. In this matrix,
M represents the number of angles specified in
ANG and L represents the number of
frequencies specified in
To use an object function, specify the
System object as the first input argument. For
example, to release system resources of a System object named
Specific to Antenna and Transducer Element System Objects
|Compute and display beamwidth of sensor element pattern|
|Directivity of antenna or transducer element|
|Antenna element polarization capability|
|Plot antenna or transducer element directivity and patterns|
|Plot antenna or transducer element directivity and pattern versus azimuth|
|Plot antenna or transducer element directivity and pattern versus elevation|
Cosine Antenna Response
Construct a cosine antenna element and find its response in one direction. The cosine response is raised to a power of 1.5 in both azimuth and elevation. The antenna frequency range lies in the X band (from 8 to 12 GHz) at 10 GHz. Obtain the antenna's response for an incident angle of 30° azimuth and 5° elevation.
antenna = phased.CosineAntennaElement('FrequencyRange',[8e9 12e9], ... 'CosinePower',1.5); fc = 10.0e9; ang = [30;5]; resp = antenna(fc,ang)
resp = 0.8013
Plot Power Response of Cosine Antenna
Construct a cosine pattern antenna and calculate its response at boresight (0 degrees azimuth and 0 degrees elevation). Then, plot the antenna pattern. Assume the antenna works between 800 MHz and 1.2 GHz and its operating frequency is 1 GHz. Set the azimuth exponent to 1.5 and elevation exponent to 2.5.
antenna = phased.CosineAntennaElement('FrequencyRange',[800e6 1.2e9],... 'CosinePower',[1.5 2.5]); fc = 1e9; resp = antenna(fc,[0;0]); pattern(antenna,fc,0,-90:90,'Type','powerdb','CoordinateSystem','polar')
Plot 3-D Polar Pattern of Cosine Antenna
Construct a cosine antenna element using default parameters. Assume the antenna operating frequency is 1 GHz. Then, plot the antenna response in 3-D polar format.
antenna = phased.CosineAntennaElement; fc = 1e9; pattern(antenna,fc,[-180:180],[-90:90],'Type','powerdb', ... 'CoordinateSystem','polar')
Directivity of Cosine Antenna
Compute the directivity of a cosine antenna element at seven azimuth directions centered around boresight (zero degrees azimuth and zero degrees elevation). All elevation angles are set to zero degrees.
Create a cosine antenna element system object with the
CosinePower exponents set to 1.8.
antenna = phased.CosineAntennaElement('CosinePower',[1.8,1.8]);
Set the directivity angles so that the elevation angles are zero. Set the frequency to 1 GHz.
ang = [-30,-20,-10,0,10,20,30; 0,0,0,0,0,0,0]; freq = 1e9;
Compute the directivity.
d = directivity(antenna,freq,ang)
d = 7×1 7.3890 8.6654 9.3985 9.6379 9.3985 8.6654 7.3890
The maximum directivity is at boresight.
Plot Azimuth-Cut of Cosine Antenna Response Pattern
Construct a cosine antenna element using default parameters. Then, plot the pattern of the field magnitude. Assume the antenna operating frequency is 1 GHz. Restrict the response to the range of azimuth angles from -30 to 30 degrees in 0.1 degree increments. The default elevation angle is 0 degrees.
antenna = phased.CosineAntennaElement; fc = 1e9; pattern(antenna,fc,[-30:0.1:30],0,'Type','efield', ... 'CoordinateSystem','polar')
Plot Directivity of Cosine Antenna
Construct a cosine-pattern antenna. Assume the antenna works between 1 and 2 GHz and its operating frequency is 1.5 GHz. Set the azimuth angle cosine power to 2.5 and the elevation angle cosine power to 3.5. Then, plot an elevation cut of its directivity.
antenna = phased.CosineAntennaElement('FrequencyRange', ... [1e9 2e9],'CosinePower',[2.5,3.5]); fc = 1.5e9; pattern(antenna,fc,0,-90:90,'Type','directivity', ... 'CoordinateSystem','rectangular')
The directivity is maximum at 0 degrees elevation and attains a value of approximately 12 dB.
Limited-Angle Azimuth Pattern of Cosine Antenna
Plot constant-elevation azimuth directivity patterns of a cosine antenna element at 0 degrees and 10 degrees elevation. Assume the operating frequency is 500 MHz.
fc = 500e6; antenna = phased.CosineAntennaElement('FrequencyRange',[100,900]*1e6, ... 'CosinePower',[3,2]); patternAzimuth(antenna,fc,[0 30])
Plot a limited range of azimuth angles by specifying the
Azimuth parameter. Note the change in scale.
Limited-Angle Elevation Pattern of Cosine Antenna
Plot constant-azimuth elevation directivity patterns of a cosine antenna element at 45 and 55 degrees azimuth. Assume the operating frequency is 500 MHz.
fc = 500e6; antenna = phased.CosineAntennaElement('FrequencyRange',[100,900]*1e6, ... 'CosinePower',[3,2]); patternElevation(antenna,fc,[45 55])
Plot a limited range of elevation angles using the Elevation parameter. Note the change in scale.
Cosine Antenna Does Not Support Polarization
Create a cosine antenna element using the
phased.CosineAntennaElement System object™ and show that it does not support polarization.
antenna = phased.CosineAntennaElement('FrequencyRange',[1.0,10]*1e9); isPolarizationCapable(antenna)
ans = logical 0
The returned value
0 shows that the antenna element does not support polarization.
The object returns the field response (also called field pattern)
of the cosine antenna element.
In this expression
az is the azimuth angle.
el is the elevation angle.
The exponents m and n are real numbers greater than or equal to zero.
The response is defined for azimuth and elevation angles between –90° and 90°, inclusive, and is always positive. There is no response at the backside of a cosine antenna. The cosine response pattern achieves a maximum value of 1 at 0° azimuth and 0° elevation. Larger exponent values narrow the response pattern of the element and increase the directivity.
The power response (or power pattern) is the squared value of the field response.
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
patternElevationobject functions are not supported.
See System Objects in MATLAB Code Generation (MATLAB Coder).