clear all;
close all;
clc;
h0=0.01;
beta=0.002070*10^(-8);
loss=0.0153;
density=1.1782;
v=1.006;
gam=3.25;
c=1500;
f=35000;
lamda=c/f;
k=2*pi/lamda;
theta=(0:1:90)*pi/180;
%Kirchhoff Approximation
kk=(1+i*loss)/v;
P=sqrt(kk^2-cos(theta).^2);
imp=density*sin(theta)./P;
R=(imp-1)./(imp+1);
r0=-20*log10(abs(R));
plot(theta*180/pi,r0);
hold on;
grid on;

h0=0.01;
beta=0.002070*10^(-8);
loss=0.0101;
density=1.74;
v=1.006;
gam=3.25;
c=1500;
f=30000;
lamda=c/f;
k=2*pi/lamda;
theta=(0:1:90)*pi/180;
%Kirchhoff Approximation
kk=(1+i*loss)/v;
P=sqrt(kk^2-cos(theta).^2);
imp=density*sin(theta)./P;
R=(imp-1)./(imp+1);
r0=-20*log10(abs(R));
plot(theta*180/pi,r0,'--');
grid on;