%圓弧陣的指向性
clear all;
close all;
m=29                        ;
N=60;
c=1500;
f=1500;
lamda=c/f;
r=lamda/0.4;
alpha=2*pi/N;
x=0:pi/180:pi;
a=0;b=0;
theter=0;
for i=-m:m
    derta=r/c*[cos(x-i*alpha)-cos(theter-i*alpha)];
    a=a+cos(2*pi*f.*derta);
    b=b+sin(2*pi*f.*derta);
end
R=sqrt(a.^2+b.^2)/(2*m+1);
plot(x,R);title('圓弧陣的指向性圖');
xlabel('入射信號角度');ylabel('指向性函數值');