%=============================================
%antnna direction diagram   with windows
%==============================================
n=10;
theta=-pi/3:0.001:pi/3;
m=length(theta);
fai=2*pi*sin(theta);
a_theta=zeros(1,m);
for l=1:m
for k=1:n
    a_theta(l)=a_theta(l)+exp(j*(k-51)*fai(l));
end
am(l)=abs(a_theta(l));

end
figure(1)
plot(theta,am);
w1=hanning(51);
[h1,f1]=freqz(w1/(sum(w1)),1,512,2);
figure(2)
plot(f1,20*log10(abs(h1)));
n=51;
theta=-pi/3:0.001:pi/3;
m=length(theta);
fai=2*pi*sin(theta);
a_theta=zeros(1,m);
for l=1:m
for k=1:n
    a_theta(l)=a_theta(l)+w1(k)*exp(j*(k-51)*fai(l));
end
am(l)=abs(a_theta(l));

end
figure(3)
plot(am);