Documentation Center

  • Trial Software
  • Product Updates

phased.HeterogeneousConformalArray System object

Package: phased

Heterogeneous conformal array

Description

The HeterogeneousConformalArray object constructs a conformal array from a heterogeneous set of antenna elements. A heterogeneous array is an array in which the antenna or microphone elements may be of different kinds or have different properties. An example would be an array of elements each having different antenna patterns. 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. Define and set up your conformal array. See Construction.

  2. Call step to compute the response according to the properties of phased.HeterogeneousConformalArray. The behavior of step is specific to each object in the toolbox.

Construction

H = phased.HeterogeneousConformalArray creates a heterogeneous conformal array System object™, H. This object models a heterogeneous conformal array formed with sensor elements whose pattern may vary from element to element.

H = phased.HeterogeneousConformalArray(Name,Value) creates object, H, 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

ElementSet

Set of elements used in the array

Specify the set of different elements used in the sensor array as a row MATLAB cell array. Each member of the cell array contains an element object in the phased package. Elements specified in the ElementSet property must be either all antennas or all microphones. In addition, all specified antenna elements should have same polarization capability. Specify the element of the sensor array as a handle. The element must be an element object in the phased package.

Default: One cell containing one isotropic antenna element

ElementIndices

Elements location assignment

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

Default: [1 2 2 1]

ElementPosition

Element positions

ElementPosition specifies the positions of the elements in the conformal array. The value of the ElementPosition property must be 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 array's local coordinate system. The local coordinate system has its origin at an arbitrary point.

Default: [0; 0; 0]

ElementNormal

Element normal directions

ElementNormal specifies the normal directions of the elements in the conformal array. Angle units are degrees. The value assigned to ElementNormal must be either a 2-by-N matrix or a 2-by-1 column vector. 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.

Default: [0; 0]

Taper

Element taper or weighting

Element tapering specified as a complex-valued scalar or a complex-valued 1-by-N row vector. 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 weights are applied to each element. If 'Taper' is a vector, each weight is applied to the corresponding sensor element.

Default: 1

Methods

cloneCreate system object with identical values
collectPlaneWaveSimulate received plane waves
getElementPositionPositions of array elements
getNumElementsNumber of elements in array
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
getTaperArray element tapers
isLockedLocked status for input attributes and nontunable properties
isPolarizationCapablePolarization capability
plotResponsePlot response pattern of array
releaseAllow property value and input characteristics changes
stepOutput responses of array elements
viewArrayView array geometry

Examples

expand all

Heterogeneous Uniform Circular Array (UCA)

Construct an 8-element heterogeneous uniform circular array (UCA). Four of the elements have a cosine pattern with a power of 1.6. The remaining four have a cosine pattern with a power of 1.5. Plot its response as a function of elevation angle. Assume a 1 GHz operating frequency. The wave propagation speed is the speed of light.

sElement1 = phased.CosineAntennaElement('CosinePower',1.6);
sElement2 = phased.CosineAntennaElement('CosinePower',1.5);
sArray = phased.HeterogeneousConformalArray(...
    'ElementSet',{sElement1,sElement2},...
    'ElementIndices',[1 1 1 1 2 2 2 2]);
N = 8; azang = (0:N-1)*360/N-180;
sArray.ElementPosition = ...
    [cosd(azang);sind(azang);zeros(1,N)];
sArray.ElementNormal = [azang;zeros(1,N)];
c = physconst('LightSpeed');
fc = 1e9;
plotResponse(sArray,fc,c,'RespCut','El','Format','Polar');

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.

See Also

| | | | | | | | | | |

Was this topic helpful?