Phased Arrays - MATLAB Simulations for Radar Systems Design - page 389

w( (xloop-1)*ratiox+1, 1:ratioy:Ny) = temprow ;
end
array = w;
else
w = array ;
% w(1:Nx, :) = array(1:N,:);
end
% Compute array pattern
arrayfft = abs(fftshift(fft2(w,nfftx,nffty))).^2 ;
%compute [su,sv] matrix
U = [-nfftx/2:(nfftx/2)-1] ./(dolx*nfftx);
indexx = find(abs(U) <= 1);
U = U(indexx);
V = [-nffty/2:(nffty/2)-1] ./(doly*nffty);
indexy = find(abs(V) <= 1);
V = V(indexy);
%Normalize to generate gain patern
rbar=sum(sum(arrayfft(indexx,indexy))) / dolx/doly/4./nfftx/nffty;
arrayfft = arrayfft(indexx,indexy) ./rbar;
[SU,SV] = meshgrid(V,U);
indx = find((SU.^2 + SV.^2) >1);
arrayfft(indx) = eps/10;
pattern = 10*log10(arrayfft +eps);
figure(1)
mesh(V,U,pattern);
xlabel('V')
ylabel('U');
zlabel('Gain pattern - dB')
figure(2)
contour(V,U,pattern)
grid
axis image
xlabel('V')
ylabel('U');
axis([-1 1 -1 1])
figure(3)
x0 = (Nx+1)/2 ;
y0 = (Ny+1)/2 ;
radiusx = dolx*((Nx-1)/2) ;
radiusy = doly*((Ny-1)/2) ;
[xxx, yyy]=find(abs(array)>eps);
xxx = xxx-x0 ;
yyy = yyy-y0 ;
plot(yyy*doly, xxx*dolx,'rx')