clear all
ht=10;hr=2;
c=3e8;R=-1; f0=1e8; fi= [1:1:1000];fd=5000000;f= f0+fd*fi; lambda=c./f;
da=[50,300,800,2000];
for i=1:length(da)
d=da(i);
d1=sqrt(d.^2+(ht-hr)^2);
d2=sqrt(d.^2+(ht+hr)^2);
Td=(d2-d1)/c
a1=exp(j*2*pi*d1./lambda)/d1;
a2=R*exp(j*2*pi*d2./lambda)/d2;
a(i,:)=abs(a1+a2);
end
figure (5)
subplot(2,2,1);plot(f,a(1,:));title('d=50m');ylabel('magnitude')
subplot(2,2,2);plot(f,a(2,:));title('d=300m');ylabel('magnitude')
subplot(2,2,3);plot(f,a(3,:)); title('d=800m');xlabel('frequency');ylabel('magnitude')
subplot(2,2,4);plot(f,a(4,:)); title('d=2000m');xlabel('frequency');ylabel('magnitude')