[color=#006400][size=14px]clc;[/size][/color][color=#006400][size=14px]clear all[/size][/color]

[color=#006400][size=14px]clf;[/size][/color]

[color=#006400][size=14px]tic;                %计时[/size][/color]

[color=#006400][size=14px]lambda=1;[/size][/color]

[color=#006400][size=14px]N=31;a=0.0000001;%已知天线和半径[/size][/color]

[color=#006400][size=14px]ii=1;[/size][/color]

[color=#006400][size=14px]for h=0.2:0.1:0.9[/size][/color]

[color=#006400][size=14px]L=h*lambda;[/size][/color]

[color=#006400][size=14px]len=L/N;%将线分成奇数段,注意首末两端的电流为0[/size][/color]

[color=#006400][size=14px]e0=8.854e-012;u0=4*pi*10^(-7);k=2*pi/lambda;[/size][/color]

[color=#006400][size=14px]c=3e+008;w=2*pi*c;%光速,角频率[/size][/color]

[color=#006400][size=14px]ata=sqrt(u0/e0);[/size][/color]

[color=#006400][size=14px]z(1)=-L/2+len/2;[/size][/color]

[color=#006400][size=14px]for n=2:N[/size][/color]

[color=#006400][size=14px]   z(n)=z(n-1)+len;[/size][/color]

[color=#006400][size=14px]end[/size][/color]

[color=#006400][size=14px]for m=1:N[/size][/color]

[color=#006400][size=14px]   for n=1:N[/size][/color]

[color=#006400][size=14px]       if (m==n)[/size][/color]

[color=#006400][size=14px]           p(m,n)=log(len/a)/(2*pi)-j*k*len/4/pi;[/size][/color]

[color=#006400][size=14px]       else[/size][/color]

[color=#006400][size=14px]          r(m,n)=sqrt((z(m)-z(n))^2+a^2);[/size][/color]

[color=#006400][size=14px]           p(m,n)=len*exp(-j*k*r(m,n))/(4*pi*r(m,n));[/size][/color]

[color=#006400][size=14px]       end[/size][/color]

[color=#006400][size=14px]   end[/size][/color]

[color=#006400][size=14px]end[/size][/color]

[color=#006400][size=14px]for m=1:N[/size][/color]

[color=#006400][size=14px]   q(m)=cos(k*z(m));[/size][/color]

[color=#006400][size=14px]   s(m)=sin(k*z(m));[/size][/color]

[color=#006400][size=14px]   t(m)=sin(k*abs(z(m)))/(j*2*ata);[/size][/color]

[color=#006400][size=14px]end[/size][/color]

[color=#006400][size=14px]pp=p(N+1:N^2-N);[/size][/color]

[color=#006400][size=14px]pp=reshape(pp,N,N-2);[/size][/color]

[color=#006400][size=14px]mat=[pp,q',s'];%构造矩阵[/size][/color]

[color=#006400][size=14px]I=mat\t';[/size][/color]

[color=#006400][size=14px]II=[0;I(1:N-2);0];%加上两端零电流[/size][/color]

[color=#006400][size=14px]Current=abs(II);[/size][/color]

[color=#006400][size=14px]x=linspace(-L/2,L/2,N);       [/size][/color]

[color=#006400][size=14px]figure(1);[/size][/color]

[color=#006400][size=14px]string=['b','g','r','y','c','k','m','r'];[/size][/color]

[color=#006400][size=14px]string1=['ko','bo','yo','co','mo','ro','go','bo'];[/size][/color]

[color=#006400][size=14px]plot(x,Current,string(ii),'linewidth',1.3);[/size][/color]

[color=#006400][size=14px]xlabel('L/\lambda'),ylabel('电流分布');[/size][/color]

[color=#006400][size=14px]grid on[/size][/color]

[color=#006400][size=14px]hold on[/size][/color]

[color=#006400][size=14px]%legend('L=0.1\lambda','L=0.2\lambda','L=0.3\lambda','L=0.4\lambda','L=0.5\lambda','L=0.6\lambda','L=0.7\lambda','L=0.8\lambda','L=0.9\lambda','L=1\lambda')[/size][/color]

[color=#006400][size=14px]legend('L=0.1\lambda','L=0.3\lambda','L=0.5\lambda','L=0.7\lambda','L=0.9\lambda','L=1.1\lambda','L=1.3\lambda','L=1.5\lambda')[/size][/color]

[color=#006400][size=14px]Zmn=1/I((N+1)/2);%%%%%%V=1v[/size][/color]

[color=#006400][size=14px]theta=linspace(0,2*pi,360);[/size][/color]