rcs_sphere.m
上传用户:szahd2008
上传日期:2020-09-25
资源大小:1275k
文件大小:1k
- % This program calculates the back-scattered RCS for a perfectly
- % conducting sphere using Eq.(13.28), and produce plots similar to Fig.10.8
- % Spherical Bessel functions are computed using series approximation and recursion.
- clear all
- eps = 0.00001;
- index = 0;
- % kr limits are [0.05 - 15] ===> 300 points
- for kr = 0.05:0.05:15
- index = index + 1;
- sphere_rcs = 0. + 0.*i;
- f1 = 0. + 1.*i;
- f2 = 1. + 0.*i;
- m = 1.;
- n = 0.;
- q = -1.;
- % initially set del to huge value
- del =100000+100000*i;
- while(abs(del) > eps)
- q = -q;
- n = n + 1;
- m = m + 2;
- del = (2.*n-1) * f2 / kr-f1;
- f1 = f2;
- f2 = del;
- del = q * m /(f2 * (kr * f1 - n * f2));
- sphere_rcs = sphere_rcs + del;
- end
- rcs(index) = abs(sphere_rcs);
- sphere_rcsdb(index) = 10. * log10(rcs(index));
- end
- figure(1);
- n=0.05:.05:15;
- plot (n,rcs,'k');
- set (gca,'xtick',[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15]);
- %xlabel ('Sphere circumference in wavelengths');
- %ylabel ('Normalized sphere RCS');
- grid;
- figure (2);
- plot (n,sphere_rcsdb,'k');
- set (gca,'xtick',[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15]);
- xlabel ('Sphere circumference in wavelengths');
- ylabel ('Normalized sphere RCS - dB');
- grid;
- figure (3);
- semilogx (n,sphere_rcsdb,'k');
- xlabel ('Sphere circumference in wavelengths');
- ylabel ('Normalized sphere RCS - dB');