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conformalArray

Create conformal antenna array

Description

The conformalArray class creates an antenna array using any element from the antenna library. You can also specify an array of any arbitrary geometry, such as a circular array, a nonplanar array, or an array with nonuniform geometry.

Conformal arrays are used in:

  • Direction-finding systems that uses circular arrays or stacked circular arrays

  • Aircraft systems due to surface irregularities or mechanical stress

Creation

Syntax

ca = conformalArray
ca = conformalArray(Name,Value)

Description

example

ca = conformalArray creates a conformal antenna array using the default antenna element, shape, and antenna positions.

example

ca = conformalArray(Name,Value) creates a conformal antenna array with additional properties specified by one or more name-value pair arguments. Name is the property name and Value is the corresponding value. You can specify several name-value pair arguments in any order as Name1, Value1, ..., NameN, ValueN. Properties not specified retain default values.

Properties

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Position of the feed or origin for each antenna element, specified as M-by-3 real matrix. M is the number of element positions. By default, M is 2. To specify additional antenna elements, add additional element positions in the conformal array.

Example: 'ElementPosition',[0.1 0.1 0.1; -0.1 -0.1 -0.1;0.2 0.0.2]

Data Types: double

Individual antenna elements in the array, specified as one of the following values:

  • A scalar

  • An array of objects

  • Cell array of objects

By default, conformal array have two antenna elements, the dipole and the bowtie. To specify additional antenna elements, add additional element positions in the conformal array. You can add both balanced and unbalanced antennas to the same conformal array.

Example: m = monopole; h = conformalArray('Element', [m,m]). Creates a conformal array consisting of two monopoles antenna elements.

Example: d = dipole; mt = monopoleTopHat; h = conformalArray('Element', {d,mt}). Creates a conformal array consisting of a dipole antenna and a monopole tophat antenna.

Data Types: cell

Position reference for the antenna element, specified as either 'origin' or 'feed'. For more information see Position Reference

Example: 'Reference','origin'

Data Types: char

Excitation amplitude of the antenna elements, specified as a scalar or a nonnegative vector. To model dead elements, set the property value to 0.

Example: 'AmplitudeTaper',3

Example: 'AmplitudeTaper',[3 0]. Creates a two-element conformal array, where 3 and 0 are the excitations amplitudes of two elements.

Data Types: double

Phase shift for antenna elements, specified as a scalar or a real vector in degrees.

Example: 'PhaseShift',[-45 -45 45 45]

Data Types: double

Tilt angle of array, specified as a scalar or vector with each element unit in degrees.

Example: 'Tilt',90

Example: 'Tilt',[90 90 0]

Data Types: double

Tilt axis of the array, specified as:

  • A three-element vector of Cartesian coordinates in meters. In this case, each vector starts at the origin and lies along the specified points on the X, Y, and Z axes.

  • Two points in space as three-element vectors of Cartesian coordinates. In this case, the antenna rotates along the line joining the two points.

  • A string input for simple rotations around the principal planes, X, Y, or Z.

For more information see, Rotate Antenna and Arrays

Example: 'TiltAxis',[0 1 0]

Example: 'TiltAxis',[0 0 0;0 1 0]

Example: 'TiltAxis','Z'

Data Types: double

Object Functions

showDisplay antenna or array structure; Display shape as filled patch
infoDisplay information about antenna or array
beamwidthBeamwidth of antenna
chargeCharge distribution on metal or dielectric antenna or array surface
correlationCorrelation coefficient between two antennas in array
currentCurrent distribution on metal or dielectric antenna or array surface
EHfieldsElectric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
impedanceInput impedance of antenna; scan impedance of array
meshMesh properties of metal or dielectric antenna or array structure
patternRadiation pattern of antenna or array; Embedded pattern of antenna element in array
patternAzimuthAzimuth pattern of antenna or array
patternElevationElevation pattern of antenna or array
returnLossReturn loss of antenna; scan return loss of array
sparametersS-parameter object

Examples

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Create a default conformal array.

c = conformalArray
c = 
  conformalArray with properties:

            Element: {[1x1 dipole]  [1x1 bowtieTriangular]}
    ElementPosition: [2x3 double]
          Reference: 'feed'
     AmplitudeTaper: 1
         PhaseShift: 0
               Tilt: 0
           TiltAxis: [1 0 0]

show(c)

Define the radius and the number of elements for the array.

r = 2;
N = 12;

Create an array of 12 dipoles.

elem = repmat(dipole('Length',1.5),1,N);

Define the x,y,z values for the element positions in the array.

del_th = 360/N;
th = del_th:del_th:360;
x = r.*cosd(th);
y = r.*sind(th);
z = ones(1,N);
pos = [x;y;z];

Create a circular array using the defined dipoles and then visualize it. Display the layout of the array.

c = conformalArray('Element',elem,'ElementPosition',pos');
show(c)
figure
layout(c)

Change the width of the fourth and the twelfth element of the circular array. Visualize the new arrangement.

c.Element(4).Width = 0.05;
c.Element(12).Width = 0.2;
figure
show(c)

Calculate and plot the impedance of the circular array at 100 MHz.The plot shows the impedance of the first element in the array.

figure
impedance(c,100e6)

To view the impedance of all the elements in the array change the value from 1 to 1:12 as shown in the figure.

Define three circular loop antennas of radii 0.6366 m(default), 0.85 m, and 1 m, repectively.

l1 = loopCircular;
l2 = loopCircular('Radius',0.85);
l3 = loopCircular('Radius',1);

Create a concentric array that uses the origin of circular loop antennas as its position reference.

c = conformalArray('Element',{l1,l2,l3},'ElementPosition',[0 0 0;0 0 0;...
    0 0 0],'Reference','origin');
show(c)

Visualize the radiation pattern of the array at 80 MHz.

pattern(c,80e6)

Create a dipole antenna to use in the reflector and the conformal array.

d = dipole('Length',0.13,'Width',5e-3,'Tilt',90,'TiltAxis','Y');

Create an infinite groundplane reflector antenna using the dipole as exciter.

rf = reflector('Exciter',d,'Spacing',0.15/2,'GroundPlaneLength',inf);

Create a conformal array using 36 dipole antennas and one infinite groundplane reflector antenna. View the array.

x = linspace(-0.4,0.4,6);
y = linspace(-0.4,0.4,6);
[X,Y] = meshgrid(x,y);
pos = [X(:) Y(:) 0.15*ones(numel(X),1)];
for i = 1:36
    element{i} = d;
end
element{37} = rf;
lwa = conformalArray('Element',element,'ElementPosition',[pos;0 0 0.15/2]);
show(lwa)

Drive only the reflector antenna with an amplitude of 1.

V = zeros(1,37);
V(end) = 1;
lwa.AmplitudeTaper = V;

Compute the radiation pattern of the conformal array.

figure
pattern(lwa,1e9,'Type','efield')

Create two patch microstrip antennas using dielectric substrate FR4. Tilt the second patch microstrip antenna by 180 degrees.

d = dielectric('FR4');
p1 = patchMicrostrip('Substrate',d);
p2 = patchMicrostrip('Substrate',d,'Tilt',180);

Create and view a conformal array using the two patch microstrip antennas placed 11 cm apart.

c = conformalArray('ElementPosition',[0 0 0;0 0 0.1100],'Element',{p1,p2})
c = 
  conformalArray with properties:

            Element: {[1x1 patchMicrostrip]  [1x1 patchMicrostrip]}
    ElementPosition: [2x3 double]
          Reference: 'feed'
     AmplitudeTaper: 1
         PhaseShift: 0
               Tilt: 0
           TiltAxis: [1 0 0]

show(c)

Create a conformal array using dipole and monopole antennas.

c = conformalArray('Element', {dipole, monopole})
c = 
  conformalArray with properties:

            Element: {[1x1 dipole]  [1x1 monopole]}
    ElementPosition: [2x3 double]
          Reference: 'feed'
     AmplitudeTaper: 1
         PhaseShift: 0
               Tilt: 0
           TiltAxis: [1 0 0]

c.ElementPosition = [0 0 0; 1.5 0 0];

Visualize the array.

figure; 
show(c);

Plot the radiation pattern of the array at 70 MHz.

pattern(c, 70e6)

Definitions

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References

[1] Balanis, Constantine A. Antenna Theory: Analysis and Design. 3rd Ed. New York: John Wiley and Sons, 2005.

Introduced in R2016a

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