Plotting 3D far field response of a phased array antenna

Question

Lawrence McCullough 2020-8-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/583301-plotting-3d-far-field-response-of-a-phased-array-antenna

回答： Raag 2025-6-24

Hi - I have an issue with trying to get the directivity response pattern for a custom phased array using the toolbox command set

My array has 8 rectangular loop elements positioned in a non-symmetrical layout around a circle in the X-Y plane

phased.ConformalArray works with no errors

viewArray works with no errors, showing the correct element configuration

plotResponse produces the following error dialogue :-

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>> loop_array

Expected one output from a curly brace or dot indexing expression, but there were 8 results.

Error in em.EmStructures/saveobj

Error in phased.internal.AbstractHomogeneousArray/saveObjectImpl (line 98)

s.Element = saveobj(obj.Element);

Error in phased.ConformalArray/saveObjectImpl (line 360)

s = saveObjectImpl@phased.internal.AbstractHomogeneousArray(obj);

Error in matlab.System/saveobj

Error in matlab.System/cloneImpl

Error in phased.internal.AbstractHomogeneousArray/cloneSensor (line 240)

newObj = clone(obj);

Error in phased.internal.plotRadiationPattern (line 123)

temp = cloneSensor(H);

Error in phased.internal.AbstractArray/plotResponse (line 622)

phased.internal.plotRadiationPattern(...

Error in loop_array (line 58)

plotResponse(array,fc,c,'RespCut','3D','Unit','dBi','Format','polar');

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The relevant code sections are :-

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c = 3e8;

az = -180:180;

elv = -90:90;

fc = 2.4e9;

frange = (1e9:0.1e9:4e9);

%

L1 = loopRectangular('Length', ll, 'Width', lw, 'Thickness', lt,'TiltAxis',[0 0 1],'Tilt',270);

L2 = loopRectangular('Length', ll, 'Width', lw, 'Thickness', lt,'TiltAxis',[0 0 1],'Tilt',90);

xpos = [ae el -el -ae -ae -el el ae];

ypos = [el ae ae el -el -ae -ae -el];

zpos = [0 0 0 0 0 0 0 0];

normal_az = [na (90-na) (90+na) (180-na) (-180+na) (-90-na) (-90+na) -na];

normal_el = [0 0 0 0 0 0 0 0];

%

array = phased.ConformalArray('Element',[L1 L2 L1 L1 L2 L1 L2 L2],'ElementPosition',[xpos;ypos;zpos],'ElementNormal',[normal_az;normal_el]);

%

hold on;

viewArray(array,'ShowNormals',true);

view(0,90);

figure;

%pattern(array,fc,az,elv,'CoordinateSystem','polar','Type','powerdb','Normalize',true,'PropagationSpeed',c);

plotResponse(array,fc,c,'RespCut','3D','Unit','dBi','Format','polar');

%

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Appreciate any insight into the source of the error as this is the first time I have used the features of this toolbox

Larry

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Answer 1

Raag 2025-6-24

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/583301-plotting-3d-far-field-response-of-a-phased-array-antenna#answer_1567067

在 MATLAB Online 中打开

Hi Lawrence,

As per my understanding, the issue you are facing arises when attempting to use the ‘plotResponse’ function with a ‘phased.ConformalArray’ object that contains multiple different antenna elements.

The error message indicates that MATLAB expects the ‘Element’ property of the array to be a single antenna object, not a list or array of different antenna types.This is a known limitation when using ‘phased.ConformalArray’ with heterogeneous elements.

To resolve this, you can define a single antenna element (e.g., a ‘loopRectangular’ object) and use it for all positions in the array.

You can still simulate different orientations using the ‘ElementNormal’ property. This approach avoids the internal object cloning error and allows ‘plotResponse’ to function correctly.

Replace the array definition section of your code with the following:

% Constants 
c = 3e8; % Speed of light 
fc = 2.4e9; % Frequency in Hz 
az = -180:180; 
elv = -90:90; 
% Loop element dimensions 
ll = 0.05; % Length 
lw = 0.01; % Width 
lt = 0.001; % Thickness 
% Element positions 
ae = 0.1; el = 0.05; na = 45; 
xpos = [ae el -el -ae -ae -el el ae]; 
ypos = [el ae ae el -el -ae -ae -el]; 
zpos = zeros(1,8); 
% Element normals 
normal_az = [na (90-na) (90+na) (180-na) (-180+na) (-90-na) (-90+na) -na]; 
normal_el = zeros(1,8); 
% Create a single loop element 
L = loopRectangular('Length', ll, 'Width', lw, 'Thickness', lt); 
% Create conformal array using the same element for all positions 
array = phased.ConformalArray( ... 
    'Element', L, ... 
    'ElementPosition', [xpos; ypos; zpos], ... 
    'ElementNormal', [normal_az; normal_el]); 
% Visualize array layout 
figure; 
viewArray(array, 'ShowNormals', true); 
view(0, 90); 
% Plot 3D far-field response 
figure; 
plotResponse(array, fc, c, 'RespCut', '3D', 'Unit', 'dBi', 'Format', 'polar'); 