%matlab script for ps2 Need N=number of elements and d=element spacing
% in wavelengths
dct=0.0002;
ct=-1:dct:1;	%define equally spaced cos(theta) vector
ct=ct+eps;	%offset slightly so cos(theta) is never zero
t=acosd(ct);	%get the corresponding theta vector
p=(1-ct.^2).*(sin(pi*N*d*ct)./sin(pi*d*ct)).^2;	%power pattern
intp=dct*sum(p);	%integrate P(cos(theta)) wrt cos(theta)
g=p*2/intp;		%normalize to get the gain
lg=10*log10(g);		%get log10(gain)
figure(1);
plot(ct,lg)
grid
ax=axis;
ax(3)=ax(4)-40;
axis(ax);
figure(2);
plot(t,lg)
grid
ax2=axis;
ax2(3)=ax2(4)-40;
axis(ax2);
%get the -3dB width in theta
gmax=max(g);
w1=find(g > gmax/2,1,'first');
w2=find(g > gmax/2,1,'last');
width=t(w1)-t(w2)