i want to plot a 2d planar array antenna using the array factor and by not using any toolbox. so far i have reffered arik d brown book on esa using matlab but im not able to get the output so far ive coded this much.

l=3e8/3.3e9;
k=2*pi/l;
theta=-80:80;
phi=-80:80;
[THETA,PHI]=meshgrid(theta,phi);
My=10;
Nz=10;
dy=l/2;
dz=l/2;
deltay=0;deltaz=0;
psiy=(k*dy*sin(THETA).*sin(PHI))+deltay;
psiz=(k*dz*sin(THETA).*cos(PHI))+deltaz;
AFy=0;
AFz=0;
for m=1:My
    AFy=AFy+exp(1i*(m-1)*psiy);
end
for n=1:Nz
    AFz=AFz+exp(1i*(n-1)*psiz);
end
AF= AFy.*AFz;
AFmag=abs(AF);
figure
surf(PHI,THETA,AFmag);
shading interp;
colormap('default');
xlabel('phi');
zlabel('directivity');
title('');

[jalil ur rehman kazim]

clear
clc
%Balanis Chapter 6 formulas 3rd edition
%Array factor of planar arrays

j=sqrt(-1);
M=361; %Angle resolution
k=2*pi; %wavenumber
theta=linspace(0,pi,M);
phi=linspace(-pi/2,pi/2,M);

[THETA,PHI]=meshgrid(theta,phi);
dtheta=pi/M;
dphi=pi/M;

%Planar Array variables
My=8; 
Nz=8;
dy=0.5; %Interelement spacing in y
dz=0.5; %Interelement spacing in z
deltay=0; %Steering angle in phi
deltaz=0; %Steering angle in theta

%Array factor

psiy=(-k*dy*sin(THETA).*sin(PHI))+deltay;
psiz=(-k*dz*cos(THETA))+ deltaz;
AFy=0;
AFz=0;

for m=1:My
    AFy= AFy+ exp(j*(m-1)*psiy);
end
for n=1:Nz
    AFz=AFz+ exp(j*(n-1)*psiz);
end
AF=AFy.*AFz;
AFmag=abs(AF);

%Directivity
Utheta=AFmag.^2;
Prad=sum(sum(Utheta.*sin(THETA)*dtheta*dphi));
D=4*pi*Utheta/Prad;

dBd=20.*log10(D);

%Directivity Plot

% figure;

surf(PHI,THETA,D);
shading interp;
colormap('default');
xlabel('\phi[deg]','Fontsize',6);
set(gca,'XTick',-pi/2:pi/6:pi/2);
set(gca,'XTickLabel',{'-90','-60','-30','0','30','60','90'},'Fontsize',10,'fontweight','bold','box','on');

ylabel('\Theta[deg]','Fontsize',6);
set(gca,'YTick',0:pi/6:pi);
set(gca,'YTickLabel',{'-90','-60','-30','0','30','60','90'},'Fontsize',10,'fontweight','bold','box','on');

zlabel('Directivity',"FontSize",10)

[Shadi ebrahimi]

Thanks.

why sin(THETA) is taken out in the above from psiz? Balanis book includes a sin(THETA) in psiz.

psiy=(-k*dy*sin(THETA).*sin(PHI))+deltay;

psiz=(-k*dz*cos(THETA))+ deltaz;

However, when I have sin(THETA) in the psiz , I can not get the AF in Balanis book. can you help answer this question. thanks.

[asher bin zafar]

Hi Shadi,

DId you find any solution? I see that yes sin(theta) should be there in the equation of psiz. Plus, it also hase cos(phi) instead of cos(theta) . But as soon as i put it i am getting an anusual directivity graph. If you could help. Thanks in advance.