function [rcs_db] = rcs_ellipsoid (a, b, c, phi)
% This program computes the back-scattered RCS for an ellipsoid.
% The angle phi is fixed, while the angle theta is varied from 0-180 deg.
% A plot of RCSversus theta is generated

eps = 0.00001;
% Enter the ellpsiod size
%a = .15; % 15 cm
%b = .20; % 20 cm
%c = .95 ; % 95 cm
% Enter angle phi
% phi = pi / 4.;
sin_phi_s = sin(phi)^2;
cos_phi_s = cos(phi)^2;
% Generate aspect angle vector
theta = 0.:.05:180;
theta = (theta .* pi) ./ 180.;
if(a ~= b & a ~= c)
   rcs = (pi * a^2 * b^2 * c^2) ./ (a^2 * cos_phi_s .* (sin(theta).^2) + ...
   b^2 * sin_phi_s .* (sin(theta).^2) + ...
   c^2 .* (cos(theta).^2)).^2 ;
else
   if(a == b & a ~= c)
      rcs = (pi * b^4 * c^2) ./ ( b^2 .* (sin(theta).^2) + ...
         c^2 .* (cos(theta).^2)).^2 ;
   else
      if (a == b & a ==c)
         rcs = pi * c^2;
      end
   end
end
rcs_db = 10.0 * log10(rcs);
figure (1);
plot((theta * 180 / pi),rcs_db);
xlabel ('Aspect angle - degrees');
ylabel ('RCS - dBsm');
%title ('phi = 45 deg, (a,b,c) = (.15,.20,.95) meter')
grid;
return