[已解决]Sullivan 写的两个程序FDTD1D_1.5和FDTD_2.1模拟相同的情景为什么输出的结果不同呀

哪位高手指点下：Sullivan 写的两个程序FDTD1D_1.5和FDTD_2.1模拟相同的情景（即正弦波通过损耗介质）为什么输出的结 .. |u<7?)mp  
"ze|W\Bv!  

未注册仅能浏览部分内容，查看全部内容及附件请先 登录 或 注册

两个都是1D的？ eJ-nKkg~a  
代码贴出来？

FDTD1D_1.5 CU!Dhm/U  
5Gm_\kd  
c7H^$_^=  
delta_x = .01;%Set the cell size to 1cm La[V$+Y  
delta_t = delta_x/(2*3e8);%Calculate the time step do'GlU oMC  
max_time = 500;% time is be limited 'LDQgC*%  
max_space = 200; t%8BK>AHvw  
E = zeros(max_space,1); 7b+6%fV  
H = E; ?}Y]|c^W  
dielectric_begin = 100; ,eS)e+yzc2  
dielectric_end = max_space; G' 1'/  
dielectic_space_a = ones(max_space,1); =7UsVn#o  
dielectic_space_b = ones(max_space,1); 5)X=*I  
eta = 0.5; 2GG2jky{/  
dielectric_constant = 4; GTHt'[t@;  
etaeps = eta/dielectric_constant; }^\oCR@  
%Lossy Medium variables - for non-Lossy medium set sigma = 0; MF'JeM;H  
sigma = 0.04; ]6j{@z?{  
epszero = 8.85419e-12; m9;SrCN_  
loss_term = (delta_t*sigma) / (2*epszero*dielectric_constant); v`T c}c '  
%ABS needed for LHS of problem space do not work with Lossy medium j1<Yg,_.p  
E_low_m2 = 0; E!F^H^~$8  
E_low_m1 = 0; Wx#;E9=Im  
E_high_m2 = 0; ))Za&S*<  
E_high_m1 = 0; *{5fq_  
%Initialize Pulse Variables ;$Jo+#  
frequency = 700*1e6;% Unit of Mhz {_*yGK48n  
place_pulse = 5; !5!<C,U  
% center_problem_space = max_space/2; xoME9u0x4  
%Set up dielectric medium within the problem space Dw"\/p:-3  
for i = 1:max_space {M)Nnst"~  
if (i>=dielectric_begin & i <= dielectric_end) .e-#
yET  
dielectric_space_a(i)=(1-loss_term)/(1+loss_term); );YDtGip J  
dielectric_space_b(i)=0.5/(dielectric_constant *(1+loss_term)); *0ro0Z|Iq  
else 8eRLy/`gd  
dielectric_space_a(i)=1; uXiN~j &Be  
dielectric_space_b(i)=eta; 2~[juWbz  
end k;Y5BB  
end gRzxLf`K  
for n = 1:max_time `WS&rmq&'  
for k = 2:max_space t6t!t*jO  
E(k) = dielectric_space_a(k)*E(k) + dielectric_space_b(k)*(H(k-1)-H(k));
B33\?Yj)  
end 3OB"#Ap8<  
%Soft Source- adds a value on the grid /gas2k==^  
pulse = sin(2*pi*frequency*delta_t*n); rvM{M/4  
E(place_pulse) = E(place_pulse) + pulse; lU]nd[x  
%ABC E y
f,z$CR  
E(1) = E_low_m2; e|r`/:M  
E_low_m2 = E_low_m1; -nwypu  
E_low_m1 = E(2); F"mmLao  
E(max_space) = E_high_m2; Vjpy~iP4B  
E_high_m2 = E_high_m1; A@u@ift  
E_high_m1 = E(max_space-1); NHE18_v5  
for j = 1:max_space-1 -'Mf\h8  
    H(j) = H(j) +eta*(E(j)-E(j+1)); c
Z3v=ke^  
end "J1 4C9u   
plot(E) 0"SU_jQzv  
title('Soft Source Simulation with Dielectric Constant = 4') [G3E%z
 
axis([0 max_space -1.2 1.2]) ?V=CB,^  
drawnow vih9KBT  
end U$UIN#  
fN2lLn9/u  
FDTD_2.1 0*v2y*2V  
TcoB,Kdce  
B<C&xDRZ0  
delta_x = .01;%Set the cell size to 1cm wuo,kM  
delta_t = delta_x/(2*3e8);%Calculate the time step /mZE/>&~,  
max_time = 500; %time is not be limited ;AG()NjOO:  
max_space = 200; 2Khv>#l  
E = zeros(max_space,1); %Electric array B-mowmJ3dg  
H = E; %Magnetic array 5lum$5  
D = E; %flux density array +w~oH=  
I = E; s#GLJl\E_P  
dielectric_begin = 100;
_e2=ado  
dielectric_end = 200; .RL=xb|[  
dielectic_space_a = ones(max_space,1); |vC~HJpuv'  
dielectic_space_b = ones(max_space,1); T> p&$]OG  
eta = 0.5; r
mOj  
dielectric_constant = 4; z(~_AN M4,  
%Lossy Medium variables - for non-Lossy medium set sigma = 0; nr3==21Om4  
sigma = 0.04; [fyLV`  
epszero = 8.85419e-12; +cRn%ioVi  
etaeps = (delta_t*sigma) / epszero; eJX#@`K  
%Initalize ABC conditions &M[?h}B6  
E_low_m2 = 0; lLIAw$  
E_low_m1 = 0; 3(UVg!t  
E_high_m2 = 0; h@BY]80  
E_high_m1 = 0; '<uq3?5  
%Initialize Pulse Variables *NQ/UXE  
frequency = 700*1e6;% Unit of Mhz cH)";]k*-  
place_pulse = 5; )M^ gT}M  
%Dielectric Medium - wave velocity slows as it travels through the medium [-x7_=E#  
for i = 1:max_space phz&zlD  
if ( i >= dielectric_begin & i <= dielectric_end ) V~ _>U}  
dielectric_space_a(i) = 1/(dielectric_constant+etaeps); 5-A\9UC*@  
dielectric_space_b(i) = etaeps; &nK<:^n  
else KY^
Z  
dielectric_space_a(i)=1; dF2RH)Ud  
dielectric_space_b(i)=0; Yr|4Fl~U  
end -n;}n:wL  
end 7-A2_!_x{  
%Main Loop ss-D(K"  
for n = 1:max_time Ea=P2:3*  
%Loop for D_x w2J<WC+_<  
for k = 2:max_space d d;T-wa}  
D(k) = D(k)+0.5*(H(k-1)-H(k)); Bbp|!+KP{(  
end eV~goj  
%Soft Source- adds a value on the grid *lb<$E]="!  
pulse = sin(2*pi*frequency*delta_t*n); @%SQFu@FJ  
D(place_pulse) = D(place_pulse)+pulse; S]{oPc[7  
%Loop for E_x _ x*3PE  
for k = 1:max_space-1 F:ELPs4"  
E(k) = dielectric_space_a(i)*(D(k)-I(k)); )pn3~t<ed  
I(k) = I(k)+dielectric_space_b(i)*E(k); UCWBYC+  
end 3gf1ownC  
%ABC E `F6C-  
E(1) = E_low_m2; :gC#hmm^  
E_low_m2 = E_low_m1; ?h2}#wg  
E_low_m1 = E(2); b`_Q8 J  
E(max_space) = E_high_m2; paMa+jhQQ  
E_high_m2 = E_high_m1; ,z?':TZ  
E_high_m1 = E(max_space-1); _vZOZKS+  
%Loop for H_y ?X;RLpEc|A  
for j = 1:max_space-1 wyG;8I  
H(j) = H(j) +eta*(E(j)-E(j+1)); y+;|
Fz  
end -K$)DvV^(E  
plot(E) %XTI-B/K  
title('Soft Source Simulation with Dielectric Constant = 4') :hA#m[  
axis([0 max_space -1.2 1.2]) XfmwVjy  
drawnow y?# Loe  
end

程序代码已经贴在上面了，哪位大侠帮忙看下，这两个程序计算相同的东西为何输出结果却不一样，Sullivan 书上说两个结果应该一样才对呀

好像两叠加系数不一样吧？

什么结果不一样？输出的E波形吗？ sNwI0o  
我看源一个是加到E上的，一个是加到D上的，源不一样，出来的电场波形当然有点区别了，但频谱分析下来应该结果是一样的。

输出的E波形不一样，如果要使得输出的E波形一样，我该怎么修改FDTD_2.1这个程序呢

去掉 e@OX_t_  
b
byg8;/  
%Soft Source- adds a value on the grid \} :PLCKT  
pulse = sin(2*pi*frequency*delta_t*n); 5o8EC" 0  
D(place_pulse) = D(place_pulse)+pulse; cjIh}:|'  
{jX2}  
%ABC E 前面加上 xlg9TvvI  
%Soft Source- adds a value on the grid g'qa}/X  
pulse = sin(2*pi*frequency*delta_t*n); 3kMf!VL  
E(place_pulse) = E(place_pulse) + pulse; w)Qp?k d  
)%@J=&G8TT  
试一下看看。

刚试过，输出的E波形还是不对

哦，不知道我Matlab删掉没，没删的话，下班后回去看一下。