rcs_isosceles.m
上传用户:szahd2008
上传日期:2020-09-25
资源大小:1275k
文件大小:1k
- function [rcs] = rcs_isosceles (a, b, freq, phi)
- % This program caculates the backscattered RCS for a perfectly
- % conducting triangular flat plate, using Eq.s (2.65) through (2.67)
- % The default case is to assume phi = pi/2. These equations are
- % valid for aspect angles less than 30 degrees
- % Users may vary wavelngth, or plate's dimensions
- % Enter a, b, and lambda
- A = a * b / 2.;
- lambda = 3.e+8 / freq;
- 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
- if (phi ~= 0 & phi ~= pi/2)
- sigmao1 = 0.25 *sin(phi)^2 .* ((2. * a / b) * cos(phi) .* ...
- sin(beta) - sin(phi) .* sin(2. .* alpha)).^2;
- fact1 = (alpha).^2 - (.5 .* beta).^2;
- fact2 = (sin(alpha).^2 - sin(.5 .* beta).^2).^2;
- sigmao = (fact2 + sigmao1) ./ fact1;
- rcs = (4. * pi * A^2 / lambda^2) .* cos(theta).^2 .* sigmao + eps;
- end
- rcsdb = 10. *log10(rcs);
- plot(theta_deg,rcsdb,'k','linewidth', 1.)
- xlabel ('Aspect angle - degrees');
- ylabel ('RCS - dBsm')
- grid