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This slide generates a 3D antenna radiation pattern plot by coherently combining patterns from uniformly spaced elements with a progressive phase shift between them. The beam direction is steered by adjusting the starting phase and phase shift amount.
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Create meshgrid of angles X,Y to plot antenna pattern over
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Set number of antenna elements n and spacing k
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Define phase p and phase shift amount s
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Loop over antenna elements, shifting phase each time
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Add up radiation pattern for each element
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Plot 3D radiation pattern surface from combined elements
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Show pattern from two view angles (angled above view and top view)
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n - number of antenna elements
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k - spacing between elements
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p - initial phase at first element
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s - phase shift amount between elements
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Varying n and k changes number of lobes
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Varying p and s steer the beam direction
< Code 1 >
function main
xstep = -10*pi:pi/10:10*pi;
ystep = -10*pi:pi/10:10*pi;;
[X,Y] = meshgrid(xstep,ystep);
n=8; % should be even integer
k=2;
p = 12*pi/4;
s = (30*pi/60);
m = 0;
Z = zeros(length(xstep));
for i = ((0:(n-1))-((n-1)/2))
[X1,Y1] = meshgrid(xstep+(i*pi/k),ystep);
Z = Z+(waveCosPh(X1,Y1,p+m*s,p));
m = m+1;
end;
hFig = figure(1,'Position',[300 300 700 280]);
subplot(1,2,1);
surface(X,Y,Z,'edgecolor','none');
xlim([-10*pi 10*pi]);ylim([-10*pi 10*pi]);zlim([-10,10]);
view([-40 70]);
set(gca,'xticklabel',[]);
set(gca,'yticklabel',[]);
set(gca,'zticklabel',[]);
set(gca,'xtick',[]);
set(gca,'ytick',[]);
set(gca,'ztick',[]);
subplot(1,2,2);
surface(X,Y,Z,'edgecolor','none');
xlim([-10*pi 10*pi]);ylim([-10*pi 10*pi]);zlim([-10,10]);
view([0 90]);
set(gca,'xticklabel',[]);
set(gca,'yticklabel',[]);
set(gca,'zticklabel',[]);
set(gca,'xtick',[]);
set(gca,'ytick',[]);
set(gca,'ztick',[]);
end
function z = waveCosPh(x,y,Ph,r)
d = sqrt(x.^2 + y.^2)-Ph;
dim = size(d);
dr = dim(1);
dc = dim(2);
for i = 1 : dr
for j = 1 : dc
if d(i,j) > r
d(i,j) = pi/2;
end;
end;
end;
%z = cos(d-Ph);
z = cos(d);
end
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