Radar Cross Section (RCS) - MATLAB Simulations for Radar Systems Design - page 567

freqGH = num2str(freq*1.e-9);
A = num2str(a);
B = num2str(b);
title (['Vertical Polarization, ','Frequency = ',[freqGH],' GHz, ', ' a = ', [A], '
m',' b = ',[B],' m']);
ylabel ('RCS -dBsm');
xlabel ('Aspect angle - deg');
legend('Eq.(11.50)','Eq.(11.62)')
figure(3)
plot (theta_deg, rcsdb_h,'k',theta_deg,rcsdb_po,'k -.');
set(gca,'xtick',[10:10:85]);
title (['Horizontal Polarization, ','Frequency = ',[freqGH],' GHz, ', ' a = ',
[A], ' m',' b = ',[B],' m']);
ylabel ('RCS -dBsm');
xlabel ('Aspect angle - deg');
legend('Eq.(11.51)','Eq.(11.62)')
Listing 11.11. MATLAB Function Ðrcs_isosceles.mÑ
function [rcs] = rcs_isosceles (a, b, freq, phi)
% This program calculates the backscattered RCS for a perfectly
% conducting triangular flat plate, using Eqs. (11.63) through (11.65)
% The default case is to assume phi = pi/2. These equations are
% valid for aspect angles less than 30 degrees
% compute area of plate
A = a * b / 2.;
lambda = 3.e+8 / freq;
phi = pi / 2.;
ka = 2. * pi / lambda;
kb = 2. *pi / lambda;
% Compute theta vector
theta_deg = 0.01:.05:89;
theta = (pi /180.) .* theta_deg;
alpha = ka * cos(phi) .* sin(theta);
beta = kb * sin(phi) .* sin(theta);
if (phi == pi / 2)
rcs = (4. * pi * A^2 / lambda^2) .* cos(theta).^2 .* (sin(beta ./ 2)).^4 ...
./ (beta./2).^4 + eps;
end
if (phi == 0)
rcs = (4. * pi * A^2 / lambda^2) .* cos(theta).^2 .* ...
((sin(alpha).^4 ./ alpha.^4) + (sin(2 .* alpha) - 2.*alpha).^2 ...
./ (4 .* alpha.^4)) + eps;
end