A Simple Program to Calculate RCS of Any Object by its 3D Model (STL)

Here's a simple program that you can use to calculate the RCS of a 3D object in MATLAB, I'm working on a python-alone GUI version that can run without MATLAB.

% Load the 3D model
model = stlread('model.stl');
% Define the radar frequency and the range of angles of view
f = 10e9; % Hz
theta = 0:1:180; % deg
% Define the material properties of the object
eps_r = 4.3; % Relative permittivity
sigma = 0.005; % Conductivity (S/m)
% Define the speed of light
c = 299792458; % m/s
% Calculate the wavelength and wave number
lambda = c/f;
k = 2*pi/lambda;
% Calculate the radar cross section for each angle of view
n = size(model.faces,1);
RCS = zeros(1,length(theta));
for j = 1:length(theta)
    for i = 1:n
        % Get the vertices of the face
        vertices = model.vertices(model.faces(i,:),:);
        % Calculate the normal vector to the face
        v1 = vertices(2,:) - vertices(1,:);
        v2 = vertices(3,:) - vertices(1,:);
        normal = cross(v1,v2);
        normal = normal./norm(normal);
        % Calculate the area of the face
        area = norm(cross(v1,v2))/2;
        % Calculate the phase shift
        delta = k*dot(normal,vertices(1,:));
        % Calculate the radar cross section
        RCS(j) = RCS(j) + (lambda^2/(4*pi))*(abs(area)^2)*(abs(sin(theta(j)*pi/180))^2)*...
            ((eps_r*cos(delta) - sqrt(eps_r - sin(theta(j)*pi/180)^2 + 1i*sigma/(eps_r*2*pi*f)))^2)/...
            (eps_r^2*abs(cos(theta(j)*pi/180))^2);
    end
end
% Display the result
plot(theta,RCS);
xlabel('Angle of View (degrees)');
ylabel('Radar Cross Section (m^2)');
title('Radar Cross Section vs. Angle of View');