phased.URA

Uniform rectangular array

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Description

The URA object constructs a uniform rectangular array (URA).

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

  1. Define and set up your uniform rectangular array. See Construction.

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

Note

Starting in R2016b, instead of using the step method to perform the operation defined by the System object™, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

Construction

H = phased.URA creates a uniform rectangular array System object, H. The object models a URA formed with identical sensor elements. Array elements are distributed in the yz-plane in a rectangular lattice. The array look direction (boresight) is along the positive x-axis.

H = phased.URA(Name,Value) creates the 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).

H = phased.URA(SZ,D,Name,Value) creates a URA object, H, with the Size property set to SZ, the ElementSpacing property set to D and other specified property Names set to the specified Values. SZ and D are value-only arguments. When specifying a value-only argument, specify all preceding value-only arguments. You can specify name-value pair arguments in any order.

Properties

Element

Phased array toolbox system object

Element specified as a Phased Array System Toolbox object. This object can be an antenna or microphone element.

Default: Isotropic antenna element with default properties

Size

Size of array

A 1-by-2 integer vector or a single integer containing the size of the array. If Size is a 1-by-2 vector, the vector has the form [NumberOfRows, NumberOfColumns]. If Size is a scalar, the array has the same number of elements in each row and column. For a URA, array elements are indexed from top to bottom along a column and continuing to the next columns from left to right. In this illustration, a 'Size' value of [3,2] array has three rows and two columns.

Default: [2 2]

ElementSpacing

Element spacing

A 1-by-2 vector or a scalar containing the element spacing of the array, expressed in meters. If ElementSpacing is a 1-by-2 vector, it is in the form of [SpacingBetweenRows,SpacingBetweenColumns]. See Spacing Between Columns and Spacing Between Rows. If ElementSpacing is a scalar, both spacings are the same.

Default: [0.5 0.5]

Lattice

Element lattice

Specify the element lattice as one of 'Rectangular' | 'Triangular'. When you set the Lattice property to 'Rectangular', all elements in the URA are aligned in both row and column directions. When you set the Lattice property to 'Triangular', elements in even rows are displaced toward the positive row axis direction. The displacement is one-half the element spacing along the row.

Default: 'Rectangular'

ArrayNormal

Array normal direction

Array normal direction, specified as one of 'x', 'y', or 'z'.

URA elements lie in a plane orthogonal to the selected array normal direction. Element boresight directions point along the array normal direction

ArrayNormal Property ValueElement Positions and Boresight Directions
'x'Array elements lie on the yz-plane. All element boresight vectors point along the x-axis.
'y'Array elements lie on the zx-plane. All element boresight vectors point along the y-axis.
'z'Array elements lie on the xy-plane. All element boresight vectors point along the z-axis.

Default: 'x'

Taper

Element tapers

Element tapers, specified as a complex-valued scalar, or 1-by-MN row vector, MN-by-1 column vector, or M-by-N matrix. Tapers are applied to each element in the sensor array. Tapers are often referred to as element weights. M is the number of elements along the z-axis, and N is the number of elements along y-axis. M and N correspond to the values of [NumberofRows, NumberOfColumns] in the Size property. If Taper is a scalar, the same taper value is applied to all elements. If the value of Taper is a vector or matrix, taper values are applied to the corresponding elements. Tapers are used to modify both the amplitude and phase of the received data.

Default: 1

Methods

Specific to phased.URA Object
beamwidth

Compute and display beamwidth of an array

collectPlaneWave

Simulate received plane waves

directivity

Directivity of uniform rectangular 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 URA array pattern

patternAzimuth

Plot URA array directivity or pattern versus azimuth

patternElevation

Plot URA array directivity or pattern versus elevation

plotGratingLobeDiagram

Plot grating lobe diagram of array

plotResponse

Plot response pattern of array

step

Output responses of array elements

viewArray

View array geometry

Common to All System Objects
release

Allow System object property value changes

Examples

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Open Live Script

Construct a 3-by-2 rectangular lattice URA. By default, the array consists of isotropic antenna elements. Find the response of each element at boresight, 0 degrees azimuth and elevation. Assume the operating frequency is 1 GHz.

array = phased.URA('Size',[3 2]);
fc = 1e9;
ang = [0;0];
resp = array(fc,ang);
disp(resp)
     1
     1
     1
     1
     1
     1

Plot the azimuth pattern of the array.

c = physconst('LightSpeed');
pattern(array,fc,[-180:180],0,'PropagationSpeed',c, ...
    'CoordinateSystem','polar','Type','powerdb','Normalize',true)

Open Live Script

This example shows how to find and plot the positions of the elements of a 5-row-by-6-column URA with a triangular lattice and a URA with a rectangular lattice. The element spacing is 0.5 meters for both lattices.

Create the arrays.

h_tri = phased.URA('Size',[5 6],'Lattice','Triangular');
h_rec = phased.URA('Size',[5 6],'Lattice','Rectangular');

Get the element y,z positions for each array. All the x coordinates are zero.

pos_tri = getElementPosition(h_tri);
pos_rec = getElementPosition(h_rec);
pos_yz_tri = pos_tri(2:3,:);
pos_yz_rec = pos_rec(2:3,:);

Plot the element positions in the yz-plane.

figure;
gcf.Position = [100 100 300 400];
subplot(2,1,1);
plot(pos_yz_tri(1,:), pos_yz_tri(2,:), '.')
axis([-1.5 1.5 -2 2])
xlabel('y'); ylabel('z')
title('Triangular Lattice')
subplot(2,1,2);
plot(pos_yz_rec(1,:), pos_yz_rec(2,:), '.')
axis([-1.5 1.5 -2 2])
xlabel('y'); ylabel('z')
title('Rectangular Lattice')

Open Live Script

Construct a 5-by-2 element URA with a Taylor window taper along each column. The tapers form a 5-by-2 matrix. 

taper = taylorwin(5);
ha = phased.URA([5,2],'Taper',[taper,taper]);
w = getTaper(ha)
w = 10×1

    0.5181
    1.2029
    1.5581
    1.2029
    0.5181
    0.5181
    1.2029
    1.5581
    1.2029
    0.5181

More About

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References

[1] Brookner, E., ed. Radar Technology. Lexington, MA: LexBook, 1996.

[2] Brookner, E., ed. Practical Phased Array Antenna Systems. Boston: Artech House, 1991.

[3] Mailloux, R. J. “Phased Array Theory and Technology,” Proceedings of the IEEE, Vol., 70, Number 3s, pp. 246–291.

[4] Mott, H. Antennas for Radar and Communications, A Polarimetric Approach. New York: John Wiley & Sons, 1992.

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

Extended Capabilities

See Also

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Topics

Introduced in R2011a

Phased Array System Toolbox Documentation

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