phased.HeterogeneousConformalArray

Heterogeneous conformal array

Description

The phased.HeterogeneousConformalArray System object™ constructs a conformal array containing a heterogeneous set of antenna elements. A heterogeneous array is an array which consists of different kinds of antenna elements or an array of different kinds of microphone elements. A conformal array can have elements in any position pointing in any direction.

To compute the response for each element in the array for specified directions:

1. Create the phased.HeterogeneousConformalArray object and set its properties.

2. Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects?

Creation

Syntax

array = phased.HeterogeneousConformalArray

array = phased.HeterogeneousConformalArray(Name=Value)

Description

array = phased.HeterogeneousConformalArray creates a heterogeneous conformal array System object, array. This object models a heterogeneous conformal array formed with different kinds of sensor elements.

array = phased.HeterogeneousConformalArray(Name=Value) creates the object, array, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1=Value1,...,NameN=ValueN).

Properties

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.

ElementSet — Set of elements used in array

one cell containing one isotropic antenna element (default)

Set of elements used in the sensor array, specified as a row MATLAB^® cell array. Elements specified in the ElementSet property must be either Phased Array System Toolbox™ antennas, microphones, or transducers System objects or Antenna Toolbox™ System object. In addition, all specified antenna elements must have the same polarization capability.

Data Types: double

ElementIndices — Elements location assignment

[1 2 2 1] (default) | length-N row vector

Elements location assignment.

The mapping of elements in the array, specified as a length-N row vector. The property assigns elements to their locations in the array using the indices into the ElementSet property. In this vector, N represents the number of elements in the array. The values in the vector specified by ElementIndices must be less than or equal to the number of entries in the ElementSet property.

Data Types: double

ElementPosition — Element positions

[0; 0; 0] (default) | 3-by-N matrix

The positions of the elements in the conformal array, specified as a 3-by-N matrix, where N indicates the number of elements in the conformal array. Each column of ElementPosition represents the position, in the form [x; y; z] (in meters), of a single element in the local coordinate system of the array. The local coordinate system has its origin at an arbitrary point.

Data Types: double

ElementNormal — Element normal directions

[0; 0] (default) | 2-by-N matrix | 2-by-1 column vector

The normal directions of the elements in the conformal array, specified as either a 2-by-N matrix or a 2-by-1 column vector. Angle units are degrees. The variable N indicates the number of elements in the array. If the value of ElementNormal is a matrix, each column specifies the normal direction of the corresponding element in the form [azimuth;elevation] with respect to the local coordinate system. The local coordinate system aligns the positive x-axis with the direction normal to the conformal array. If the value of ElementNormal is a 2-by-1 column vector, it specifies the pointing direction of all elements in the array.

You can use the ElementPosition and ElementNormal properties to represent any arrangement in which pairs of elements differ by certain transformations. The transformations can combine translation, azimuth rotation, and elevation rotation. However, you cannot use transformations that require rotation about the normal.

Data Types: double

Taper — Element taper or weighting

1 (default) | complex-valued scalar | 1-by-N row vector | N-by-1 column vector

Element tapering or weighting, specified as a complex-valued scalar, 1-by-N row vector, or N-by-1 column vector. The quantity N is the number of elements in the array as determined by the size of the ElementIndices property. Tapers, also known as weights, are applied to each sensor element in the sensor array and modify both the amplitude and phase of the received data. If Taper is a scalar, the same taper value is applied to all elements. If Taper is a vector, each taper value is applied to the corresponding sensor element.

Data Types: double

Usage

Syntax

RESP = array(FREQ,ANG)

Description

RESP = array(FREQ,ANG) returns the array elements’ responses RESP at operating frequencies specified in FREQ and directions specified in ANG.

Input Arguments

FREQ — Operating frequencies of array

positive-valued length-L row vector

Operating frequencies of array, specified as a length-L row vector. Values are within the frequency range of an array element, specified by either the FrequencyRange or FrequencyVector property, depending on the type of element in the array. The element has zero response at frequencies outside that range. Units are in Hz.

Data Types: double

ANG — Response direction

real-valued 2-by-M matrix | real-valued row vector of length M

Response direction, specified as. a real-valued 2-by-M matrix or a real-valued row vector of length M. Units are in degrees,

If ANG is a 2-by-M matrix, each column of the matrix specifies the direction in the form [azimuth;elevation]. The azimuth angle must lie between –180° and 180°, inclusive. The elevation angle must lie between –90° and 90°, inclusive.

If ANG is a row vector of length M, each element specifies the azimuth angle of the direction. In this case, the corresponding elevation angle is assumed to be 0°.

Data Types: double

Output Arguments

RESP — Voltage responses of the phased array

N-by-M-by-L MATLAB array | struct

Voltage responses of the phased array. The output depends on whether the array supports polarization or not.

• If the array is not capable of supporting polarization, the voltage response, RESP, has the dimensions N-by-M-by-L. N is the number of elements in the array. The dimension M is the number of angles specified in ANG. L is the number of frequencies specified in FREQ. For any element, the columns of RESP contain the responses of the array elements for the corresponding direction specified in ANG. Each of the L pages of RESP contains the responses of the array elements for the corresponding frequency specified in FREQ.

• If the array is capable of supporting polarization, the voltage response, RESP, is a MATLAB struct containing two fields, RESP.H and RESP.V. The field, RESP.H, represents the array’s horizontal polarization response, while RESP.V represents the array’s vertical polarization response. Each field has the dimensions N-by-M-by-L. N is the number of elements in the array, and M is the number of angles specified in ANG. L is the number of frequencies specified in FREQ. Each column of RESP contains the responses of the array elements for the corresponding direction specified in ANG. Each of the L pages of RESP contains the responses of the array elements for the corresponding frequency specified in FREQ.

Object Functions

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 obj, use this syntax:

release(obj)

Specific to phased.HeterogeneousConformalArray

beamwidth	Compute and display beamwidth of an array
collectPlaneWave	Simulate received plane waves
directivity	Directivity of heterogeneous conformal array
getElementNormal	Normal vector to array elements
getElementPosition	Positions of array elements
getNumElements	Number of elements in array
getTaper	Array element tapers
isPolarizationCapable	Polarization capability
pattern	Plot heterogeneous conformal array pattern
patternAzimuth	Plot heterogeneous conformal array directivity or pattern versus azimuth
patternElevation	Plot heterogeneous conformal array directivity or pattern versus elevation
perturbations	Perturbations defined on array
perturbedArray	Apply perturbations to phased array
perturbedPattern	Display pattern of perturbed array
viewArray	View array geometry

Common to All System Objects

step	Run System object algorithm
release	Release resources and allow changes to System object property values and input characteristics
reset	Reset internal states of System object

Examples

Compute Response of Circular Conformal Array

Construct an 8-element uniform circular array using the phased.HeterogeneousConformalArray System object™. Assume the operating frequency is 1 GHz. Find the response of each element in this array in the direction of 30° azimuth and 5°.

antenna1 = phased.CosineAntennaElement('CosinePower',1.5);
antenna2 = phased.CosineAntennaElement('CosinePower',1.8);
N = 8;
azang = (0:N-1)*360/N-180;
array = phased.HeterogeneousConformalArray(...
    'ElementPosition',...
    [cosd(azang);sind(azang);zeros(1,N)],...
    'ElementNormal', zeros(2,N),...
    'ElementSet',{antenna1,antenna2},...
    'ElementIndices',[1 1 1 1 2 2 2 2]);
fc = 1e9;
ang = [30;5];
resp = array(fc,ang)

resp = 8×1

    0.8013
    0.8013
    0.8013
    0.8013
    0.7666
    0.7666
    0.7666
    0.7666

Heterogeneous Uniform Circular Array

Construct an 8-element heterogeneous uniform circular array (UCA) using the ConformalArray System object™. Four of the elements have a cosine pattern with a power of 1.6 while the remaining elements have a cosine pattern with a power of 2.0. Plot the 3-D power response. Assume a 1 GHz operating frequency. The wave propagation speed is the speed of light.

Construct the Array

sElement1 = phased.CosineAntennaElement(CosinePower=1.6);
sElement2 = phased.CosineAntennaElement(CosinePower=2.0);
N = 8;
azang = (0:N-1)*360/N-180;
sArray = phased.HeterogeneousConformalArray(...
    ElementSet={sElement1,sElement2}, ...
    ElementIndices=[1 1 1 1 2 2 2 2], ...
    ElementPosition=[cosd(azang);sind(azang);zeros(1,N)], ...
    ElementNormal=[azang;zeros(1,N)]);
c = physconst("LightSpeed");
fc = 1e9;

Create the 3-D Power Pattern

pattern(sArray,fc,[-180:180],[-90:90], ...
    CoordinateSystem="polar", ...
    Type="power")

References

[1] Josefsson, L. and P. Persson. Conformal Array Antenna Theory and Design. Piscataway, NJ: IEEE Press, 2006.

[2] Van Trees, H. Optimum Array Processing. New York: Wiley-Interscience, 2002.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The pattern, patternAzimuth, patternElevation, and viewArray object functions are not supported.

• See System Objects in MATLAB Code Generation (MATLAB Coder).

Version History

Introduced in R2013a