% Smart Antennas figure 4.25 plotting 3-d circular array patterns 
th0=input('What is the steering angle for \theta0?')
ph0=input('What is the steering angle for \phi0?')
th0=th0*pi/180;
ph0=ph0*pi/180;
a=1;
N=10;
phinc=2*pi/N;
th=[0:100]*pi/100;
ph=[0:100]*2*pi/100;
[Th,Ph]=meshgrid(th,ph);
AF=zeros(length(Th(:,1)),length(Ph(1,:)));
for n=1:N
    AF=AF+exp(-1j*2*pi*a*(sin(Th).*cos(Ph-(n-1)*phinc)-sin(th0)*cos(ph0-(n-1)*phinc)));
end
AFn=AF/max(max(abs(AF)));
figure;
x=abs(AFn).*sin(Th).*cos(Ph);
y=abs(AFn).*sin(Th).*sin(Ph);
z=abs(AFn).*cos(Th);
figure;
mesh(x,y,z)
colormap([0 0 0])
axis square
axis equal
view(118,22)
xlabel('x')
ylabel('y')
zlabel('z')
zoom(1.2)
grid off
axis off