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1、%FDTD_2D_RCSclear;clc;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*******************************初始化***********************************%%tic;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%v=3*10^8;%波速f=
2、15*10^(9);%頻率lamda=v/f;%波長k=2*pi/lamda;%波數epsz=1/(4*pi*9*10^9);%真空介電常數mu=4*pi*10.^(-7);%真空磁導率Z=sqrt(mu/epsz);%真空波阻抗epsilon=1;%相對介電常數sigma=0.0;%電導率%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%N=120;%網格數量L=1000;%迭代次數ddx=lamda/20;%網格尺寸d
3、t=ddx/(2*v);%時間間隔lstart=1;%空間起始行坐標lend=N;%空間終止行坐標rstart=1;%空間起始列坐標rend=N;%空間終止列坐標ia=N/4;%總場區(qū)域x左ib=3*N/4;%總場區(qū)域x右ja=ia;%總場區(qū)域x下jb=ib;%總場區(qū)域x上pa=ia-5;%外推區(qū)域x左pb=ib+5;%外推區(qū)域x右qa=pa;%外推區(qū)域x下qb=pb;%外推區(qū)域x上length=pb-pa+1;%每個邊上的總長度npml=N/8;%PML點數%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
4、%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%方柱參數side=2*lamda;%方柱邊長halfgrid=round(side/(2*ddx));%方柱占據網格大小%%媒質參數fori=lstart:lend;%控制媒質分部區(qū)域forj=rstart:rend;ga(i,j)=1/(epsilon+sigma*dt/epsz);%求和參量gb(i,j)=sigma*dt/epsz;%求和參量end;end;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
5、%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%源參數spread=8;%脈沖寬度t0=25;%脈沖高度is=N/2;%源的X位置js=N/2;%源的Y位置%%輸入平面波ez_inc=zeros(1,N);hx_inc=zeros(1,N);%%平面波吸收條件變量初始化ez_v1=0;ez_v2=0;ez_v3=0;ez_v4=0;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6、迭待電磁場參量dz=zeros(N,N);%z方向電荷密度ez=zeros(N,N);%z方向電場iz=zeros(N,N);%z方向電場求和參量hx=zeros(N,N);%x方向磁場hy=zeros(N,N);%y方向磁場ihx=zeros(N,N);%x方向磁場參量ihy=zeros(N,N);%y方向磁場參量%%相位和幅度提取(傅里葉變換)ine=0;inh=0;ez_out=zeros(4,length+1);hx_out=zeros(4,length);hy_out=zeros(4,length);%%%%%
7、%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*********************************PML設置********************************%%%%PML初始化fori=1:N;gi2(i)=1;gi3(i)=1;fi1(i)=0;
8、fi2(i)=1;fi3(i)=1;end;forj=1:N;gj2(j)=1;gj3(j)=1;fj1(j)=0;fj2(j)=1;fj3(j)=1;end;%%阻抗?jié)u變設置fori=1:npml+1;xnum=npml-i+1;xxn=xnum/npml;xn=0.33*(xxn^3);gi2(i)=1/(1+x
