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时域有限差分法 FDTD
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紧急求助 2D FDTD 程序 &nbs ..
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紧急求助 2D FDTD 程序 会的指点一下 万分感谢
离线
flanky
UID :19721
注册:
2008-10-21
登录:
2011-11-15
发帖:
62
等级:
仿真一级
0楼
发表于: 2009-05-09 12:51:56
— 本帖被 destroyer 从 【互助速问速答有求速应】 移动到本区(2009-11-28) —
ic=Nx/4; % 源的X位置
Sy*p6DP
jc=Ny/4; % 源的Y位置
.UN?Ak*R
^x(s!4d]
for i=1:Nx+1;
d[H`Fe6h
for j=1:Ny+1;
YiL^KK
dz(i,j)=0; %z方向电位移
0E3;f;'X
ez(i,j)=0; % z方向电场
NUh%\{
hx(i,j)=0; % x方向磁场
z-]ND
hy(i,j)=0; % y方向磁场
j39"iAn
ihx(i,j)=0;
JnQ@uZb`
ihy(i,j)=0;
p]s)Xys
iz(i,j)=0; % z方向求和中间参量
@,G\`;Ma
end;
LH@Kn?R6
end;
o=lZl_5/u;
v}!^RW'X
for i=2:Nx;
CqX*.j{
for j=2:Ny;
]R09-s 0$7
ga(i,j)=1;
]-+l.gVFW
end;
)C0Iy.N-
end;
>B$ IrM7J
%PML参数的设置
p~(STHDe#
for i=1:Nx;
_3g!_
gi2(i)=1;
( YZ2&
gi3(i)=1;
$.ctlWS8l{
fi1(i)=0;
elD|b=(-
fi2(i)=1;
~xJr|_,gp
fi3(i)=1;
NQOf\.#g
end
VhnIr#L+
qckRX+P`
for j=1:Ny;
x'Nc}
gj2(j)=1;
OwDwa~
gj3(j)=1;
-0k{O@l"
fj1(j)=0;
Kb/qM}jS
fj2(j)=1;
c[vFh0s"m
fj3(j)=1;
']^]z".H
end
:8v? 6Q
Xoq -
for i=1:npml+1; %设置PML层中的参数
@y eAM7
xnum=npml+1-i;
!b$~Sm)
xn=0.33*(xnum/npml)^3; %这里的0.333并不是严格的计算,而是经验值
bXM&VW?OP
gi2(i)=1.0/(1+xn);
8|!"CQJ|H
gi2(Nx-1-i)=1/(1+xn);
T$DFTr\\
gi3(i)=(1-xn)/(1+xn);
Cf v1nUW
gi3(Nx-1-i)=(1-xn)/(1+xn);
['6Sq@c)
^7:UC\_
xn=0.25*((xnum-0.5)/npml)^3; %这里的0.25和0.333也是一个道理
m.5@qmQ
fi1(i)=xn;
W_ ;b e
fi1(Nx-2-i)=xn;
%r(qQM.Pl
fi2(i)=1.0/(1+xn);
3"Kap/[h
fi2(Nx-2-i)=1/(1+xn);
B" ]a8}u
fi3(i)=(1-xn)/(1+xn);
Y$ KR\ m
fi3(Nx-2-i)=(1-xn)/(1+xn);
X7?14W
end
;jKL B^4nX
pQ ul0]
for i=1:npml+1;
8&1xb@Nc7
xnum=npml+1-i;
v>j<ky
xn=0.33*(xnum/npml)^3;
9zLeyw\
gj2(i)=1.0/(1+xn);
],zp~yVU&
gj2(Ny-1-i)=1/(1+xn);
-_Z
gj3(i)=(1-xn)/(1+xn);
*iSE)[W
gj3(Ny-1-i)=(1-xn)/(1+xn);
+mO/9m
SK@lr
xn=0.25*((xnum-0.5)/npml)^3;
O_DT7;g
fj1(i)=xn;
'+GYw$
fj1(Ny-2-i)=xn;
3]&le[.
`0W+(9}
fj2(i)=1.0/(1+xn);
+ =U9<8
fj2(Ny-2-i)=1/(1+xn);
Q:ql~qew
fj3(i)=(1-xn)/(1+xn);
<#./q LSR
fj3(Ny-2-i)=(1-xn)/(1+xn);
>v1.Gm
end
(r1"!~d@
,n UovWN07
%2.迭代求解电场和磁场
Yqt~h
90=gP
for t=1:T;
n(Um/
for i=2:Nx; % 为了使每个电场周围都有磁场进行数组下标处理
=,s5>2
for j=2:Ny;
|B2>}Y/
dz(i,j)=gi3(i)*gj3(j)*dz(i,j)+gi2(i)*gj2(j)*0.5*(hy(i,j)-hy(i-1,j)-hx(i,j)+hx(i,j-1)); %
\MAv's4b@
end;
++|e z{
end; % 电场循环结束
7VLn$q]:
t<^7s9r;I
pulse=sin(2*pi*f*t*dt); % 正弦波源
$?OQtz@
%pulse=exp(-4*pi*(t*dt-t0)^2/(2/f)^2);高斯脉冲情况
sei%QE]!/
dz(ic,jc)=dz(ic,jc)+pulse; %软源,就是为了防止反射做的一个处理
M2qor.d
0^d<@\
for i=1:Nx; %为了使每个电场周围都有磁场进行数组下标处理
!H9zd\wc
for j=1:Ny;
D3+<16[,
ez(i,j)=ga(i,j)* dz(i,j); %反映煤质的情况都是放到这里的
OskQ[ e0
end;
*M$$%G(4
end; % 电荷密度循环结束
&mba{O
ndvt $*
for j=1:Ny;
vU#>3[aC
ez(1,j)=0;
}fhGofN$e
ez(Nx,j)=0;
BMn`t@ !x
end
}C JK9*Z
\rH0=~F-P
for i=1:Nx;
7?uIl9Vk>(
ez(i,1)=0;
@~i :8
ez(i,Ny)=0;
SU. $bsu
end
WjvgDNk
FlbM(ofY
for i=1:Nx; % 为使每个磁场周围都有电场进行数组下标处理
hu~XFRw15
for j=1:Ny-1;
,jy9\n*<t9
curl_e=ez(i,j)-ez(i,j+1);
:4Y5
ihx(i,j)=ihx(i,j)+fi1(i)*curl_e;
R{9G$b1Due
hx(i,j)=fj3(j)*hx(i,j)+fj2(j)*0.5*(curl_e+ihx(i,j));
>ATccv
end;
QC1\Sn /
end; % 磁场HX循环结束
Ma ]*Pled
H00iy$R
for i=1:Nx-1; % 为了使每个磁场周围都有电场进行数组下标处理
y@ c[S;
for j=1:Ny;
T4;gF6(0]
curl_e=ez(i+1,j)-ez(i,j);
]C-a[
&n ..
]1q`N7
J(,{ -d-E
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条评分
离线
flanky
UID :19721
注册:
2008-10-21
登录:
2011-11-15
发帖:
62
等级:
仿真一级
1楼
发表于: 2009-05-05 20:36:59
谁对FDTD比较擅长的,帮小弟一把,谢谢,这是一个用FDTD仿真2维TM波金属方柱散射
% FDTD_2D_RCS
1krSX2L
% 本程序实现FDTD仿真2维TM波金属方柱散射
Z^#u n
% TM波沿Y方向传播,X方向极化
T<o8lL
% 采用UPML吸收,脉冲源激励
iB5'mb*
ria.MCe\!
|}wT/3>\
"; mlQyP
% 20050330
X>U _v
% 模拟区域的范围以及编号的处理:
\ 9#X]H
% 数字代表区域方向上的编号;
@$5=4HA
% ------------------------------------------------------
F_nXsKem
% | | BACK PML 2 | |
f<3lxu
% ------------------------------------------------------
a[NR%Xq
% |L | __________________________________ /| R|
TECp!`)j"
% |E | | | (ib,jb) | I|
sv+6#
% |F | | | | G|
y`8jz,&.
% |T | | | | H|
k;l^y%tzp
% |3 | | MAIN GRID | | T|
P$6Pe>3
% |P | | | |4 |
W@Rb"5Gy+
% |M | | | | P|
P5&8^YV`N
% |L | | | | M|
|F&02f!]@
% | |/ |__________________________________| | L|
)8_MkFQe
% -----------------------------------------------------
!3 zN [@w,
% | | FRONT PML 1 | |
ma@!"Z8S
% -----------------------------------------------------
n {..Q,z
!xEGN@
3|4<SMm
OZQN&7
@oQ"FLF.
clear;clc;
/?u]Fj
% load('rcs1');
KxQMPtHstz
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
T%SK";PAU$
%%*******************************初始化***********************************%%
&A~hM[-
tic;
F[]6U/g n
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
$ U-#woXa
v=3*10^8; % 波速
jt3=<&*Bm
f=0.3*10^(9); % 频率
@nIoIz D~
lamda=v/f; % 波长
8+8L'Yv;
k=2*pi/lamda; % 波数
m[s$) -T
zEi\#Zg$
epsz=1/(4*pi*9*10^9); % 真空介电常数
'CCAuN>J
mu=4*pi*10.^(-7); % 真空磁导率
O6Y1*XTmH6
Z=sqrt(mu/epsz); % 真空波阻抗
h8icF}m
epsilon=1; % 相对介电常数
Y-~MkB
sigma=0.0; % 电导率
u]&+TR
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3|bbJ6*.<
N=120; % 网格数量
q I*7ToBJ
L=1000; % 迭代次数
i-R}O6
ddx=lamda/20; % 网格尺寸
gpogv -
dt=ddx/(2*v); % 时间间隔
qD,/Qu62
+6:jm54
lstart=1; % 空间起始行坐标
|2Uw8M7.E
lend=N; % 空间终止行坐标
u4ZOHy_O^
rstart=1; % 空间起始列坐标
Ht|"91ZC5
rend=N; % 空间终止列坐标
)a<MW66
Em(Okr,0
ia=N/4; % 总场区域x左
X~Hm.qIR
ib=3*N/4; % 总场区域x右
C0CJ;
ja=ia; % 总场区域x下
$.zd,}l@L
jb=ib; % 总场区域x上
D+{&zo
;KT/;I
pa=ia-5; % 外推区域x左
+-qa7
pb=ib+5; % 外推区域x右
Zm6|aHx8v
qa=pa; % 外推区域x下
\w)ddc!ZS
qb=pb; % 外推区域x上
2Mj_wc
length=pb-pa+1; % 每个边上的总长度
v[O?7Np
g9j&\+h^
npml=N/8; % PML点数
'u6n,yRm
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
LR3>_t
%% 方柱参数
2IXtIE
side=2*lamda; % 方柱边长
Y)D F.ca(
halfgrid=round(side/(2*ddx)); % 方柱占据网格大小
h;):TFiC
HJt '@t=Ak
%% 媒质参数
e <+b?@}=B
for i=lstart:lend; % 控制媒质分部区域
I!T=$Um
for j=rstart:rend;
f9vitFkb+
ga(i,j)=1/(epsilon+sigma*dt/epsz); % 求和参量
^7YZ>^
gb(i,j)=sigma*dt/epsz; % 求和参量
5-UrHbpCZ#
end;
C]Q}HI#G
end;
12tk$FcY8*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
<TgVU.*
%% 源参数
WG +]
spread=8; % 脉冲宽度
Ru4M7%
t0=25; % 脉冲高度
pRA%07?W
is=N/2; % 源的X位置
/q) H0b
js=N/2; % 源的Y位置
2x~Pq_?y
<7`U1DR=
%% 输入平面波
bZpx61h|
ez_inc=zeros(1,N);
Ezr q2/~Q
hx_inc=zeros(1,N);
uzIM?.H
?%$~Bb _
%% 平面波吸收条件变量初始化
K|=va>
ez_v1=0;
-FW^fGS+
ez_v2=0;
+3Z+#nGtk
ez_v3=0;
:"cKxd
ez_v4=0;
ahFK^ #s
!\cVe;<r
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
HQMug
%% 迭待电磁场参量
mSGpxZ,IE
dz=zeros(N,N); % z方向电荷密度
(,b\"Q
ez=zeros(N,N); % z方向电场
]d.e(yCuE
iz=zeros(N,N); % z方向电场求和参量
K9+\Z
hx=zeros(N,N); % x方向磁场
nX8ulGG s
hy=zeros(N,N); % y方向磁场
`W.g1"o8W4
ihx=zeros(N,N); % x方向磁场参量
Xh }G=1}
ihy=zeros(N,N); % y方向磁场参量
l[[^]__
#"fn;
%% 相位和幅度提取(傅里叶变换)
LuVL<W
ine=0;
[}dPn61
inh=0;
Y++n0sK5<
ez_out=zeros(4,length+1);
4K*st8+bl-
hx_out=zeros(4,length);
"^wIixOH5
hy_out=zeros(4,length);
V>c !V9w
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
3AAciMq}
|-z"6F r-
~zVe?(W
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
o>|DT(Ib
%%*********************************PML设置********************************%%
eOx8D|^W
%% PML初始化
/4|_A {m{m
for i=1:N;
1\nzfxx
gi2(i)=1;
p!DOc8a.\e
gi3(i)=1;
[}l#cG6 k
fi1(i)=0;
|XV`A)=f
fi2(i)=1;
$i1:--~2\
fi3(i)=1;
w:x[kA
end;
4vV\vXT *
for j=1:N;
AuZISb%6
gj2(j)=1;
RwhKW?r+
gj3(j)=1;
1fC)&4W
fj1(j)=0;
IkO[R1K
fj2(j)=1;
_%#Uh#7P$
fj3(j)=1;
NMUF)ksjN
end;
a'r1or4
bz.sWBugR
%% 阻抗渐变设置
ppGWh
for i=1:npml+1;
%,e,KcP'
xnum=npml-i+1;
1 hD(l6tG@
xxn=xnum/npml;
<C451+95
xn=0.33*(xxn^3);
U2CC#,b!(
gi2(i)=1/(1+xn);
f,ZJFb98
gi2(N-i+1)=1/(1+xn);
M{SJ8+G
gi3(i)=(1-xn)/(1+xn);
Y*IKPnPot2
gi3(N-i+1)=(1-xn)/(1+xn);
A(H2Gt D
&P"1 3]^@
xxn=(xnum-0.5)/npml;
w|ahb
xn=0.25*(xxn^3);
%evtIU<h
fi1(i)=xn;
?Ezy0>j
fi1(N-i)=xn;
[Y j:H
fi2(i)=1/(1+xn);
(p]S
fi2(N-i)=1/(1+xn);
u?F.%j-
fi3(i)=(1-xn)/(1+xn);
trB-(B%5
fi3(N-i)=(1-xn)/(1+xn);
oTrit_@3
end;
| >'q%xK
8dCRSU
for j=1:npml+1;
_9q byhS7
xnum=npml-j+1;
`?SC.KT
xxn=xnum/npml;
X*9-P9x(6
xn=0.33*(xxn^3);
Mi\- 9-
gj2(j)=1/(1+xn);
{ft |*
gj2(N-j+1)=1/(1+xn);
W }v ,6Oe
gj3(j)=(1-xn)/(1+xn);
EAy@kzY?
gj3(N-j+1)=(1-xn)/(1+xn);
h6n!"z8H
9$D}j"
xxn=(xnum-0.5)/npml;
5sNN:m
xn=0.25*(xxn^3);
<p-@XzyE
fj1(j)=xn;
M^Tm{`O!
fj1(N-j)=xn;
y=Z[_L!xr
fj2(j)=1/(1+xn);
.zTkOkL
fj2(N-j)=1/(1+xn);
mF UsTb]f
fj3(j)=(1-xn)/(1+xn);
Pq@-`sw
fj3(N-j)=(1-xn)/(1+xn);
gtT&97tT<
end;
C|[x],JCS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
mA"[x_
%%***************************迭代求解电场和磁场****************************%%
o-JB,^TE
<$d2m6 J
for T=1:L;
1.TIUH1
disp(T);
v6Wz:|G/u
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
XVb9)a
%%*************************电场由磁场更新*********************************%%
m/,80J8L+f
<PM.4B@
%% TM波Y方向传播
(:\L@j
for j=2:N-1;
z?F`)}
ez_inc(j)=ez_inc(j)+0.5*(hx_inc(j-1)-hx_inc(j));
q=-h#IF^
end;
J#jFX F\
p<?lF
%% 平面波吸收条件
1Zi` \N4T
ez_inc(1)=ez_v2;
]2YC7
ez_v2=ez_v1;
Y*{5'q+2
ez_v1=ez_inc(2);
\HG4i/V:h
DLD9
ez_inc(N)=ez_v3;
@"wX#ot
ez_v3=ez_v4;
,_s.amL3O{
ez_v4=ez_inc(N-1);
2 /*z5
N(3Bzd)
%% 入射电场傅里叶变换(必须用边界加入)
YY(_g|;?8
% 注意:当计算频谱用的是其他的位置的入射波时候,会产生很大的误差;
mn*}U R
$s-B
ine=ine+exp(-sqrt(-1)*2*pi*f*T*dt)*ez_inc(ja-1);
sH'0utD#Y
Cl3L)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
y&bZai8WlE
%% 电荷密度Dz
sx]{N
for i=2:N-1; % 为了使每个电场周围都有磁场进行数组下标处理
gZBKe!@a|
for j=2:N;
|WSpWsr,
dz(i,j)=gi3(i)*gj3(j)*dz(i,j)+gi2(i)*gj2(j)*0.5*( hy(i,j)-hy(i-1,j)-hx(i,j)+hx(i,j-1) );
L\5:od[EP
end;
%9J:TH9E)
end;
)rlkQ'DN
Db;>MWt+e
%% 脉冲或正弦源的加入
*'tGi_2?(
source=exp((-0.5)*((t0-T)/spread ).^2); % 脉冲源
Q laoa)d#
% source=sin(2*pi*f*T*dt); % 正弦波源
W39J)~D^@
ez_inc(1)=source; % TM平面波源
f2&6NC;
%dz(is,js)=source; % 源
p"- %~%J=
% dz(is,js)=source;
}E[vW
salDGsW^
%% 电荷密度Dz加入射场
[:qJ1^U U
for i=ia:ib;
06Q9X!xD
dz(i,ja)=dz(i,ja)+0.5*hx_inc(ja-1);
?P4y$P
dz(i,jb)=dz(i,jb)-0.5*hx_inc(jb);
hpYv*WH:
end;
d|)ARRW
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0AF,} &$
%% 电场Ez
:Nwv&+
for i=1:N;
=#[t!-@
for j=1:N;
OW@"j;6 3`
ez(i,j)=ga(i,j)*( dz(i,j)-iz(i,j) );
Y3s8@0b3
iz(i,j)=iz(i,j)+gb(i,j)*ez(i,j) ;
B-$zioZ
end;
94|ZY}8|f
end;
[_(uz,'
%d40us8 E
%% 边界电场置零,作为辅助PML
~b0l?P*Ff
for j=1:N;
3<N2ehi?
ez(1,j)=0;
eVB43]g
ez(N,j)=0;
.o,-a >jL
end;
t o8J
7FD,TJs
for i=1:N;
3x7fa^umR
ez(i,1)=0;
:(.:bf
ez(i,N)=0;
t0kZFU
end;
}Kp$/CYd
N}<!k#d E
z`I%3U5(
%% 金属边界条件
lj:.}+]r
for i=N/2-halfgrid:N/2+halfgrid-1;
V~Z)^.6
for j=N/2-halfgrid:N/2+halfgrid-1;
5|>ms)[RQ
ez(i,j)=0;
{K}Dpy
end;
5e1oxSU
end;
a=x&sz\x
uFhPNR2l
DiY74D
% 傅里叶变换Ez;
zAvI f
s=0;
#W l^!)#j?
for i=pa:pb+1;
VS_\bIC
s=s+1;
(FZ8T39
ez_out(1,s)=ez_out(1,s)+exp(-sqrt(-1)*2*pi*f*T*dt)*ez(i,qa); % 下
qFLt/ >
ez_out(2,s)=ez_out(2,s)+exp(-sqrt(-1)*2*pi*f*T*dt)*ez(i,qb); % 上
M?Q\ Hw
end;
#$L/pRC
s=0;
O1\25D
for j=qa:qb+1;
|1/8m/2Af.
s=s+1;
g_k95k3V'
ez_out(3,s)=ez_out(3,s)+exp(-sqrt(-1)*2*pi*f*T*dt)*ez(pa,j); % 左
b'`XFB#V
ez_out(4,s)=ez_out(4,s)+exp(-sqrt(-1)*2*pi*f*T*dt)*ez(pb,j); % 右
B1s&2{L6K
end;
-[pfLo
x\yr~$}(J
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
;]=@;? 9
UV av^<_
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!0|&f>y
%%*************************磁场由电场更新*********************************%%
-*hPEgcV9
2"j&_$#l5X
%% 更新平面波磁场
Ey%[t
for j=1:N-1;
2PUB@B' +
hx_inc(j)=hx_inc(j)+0.5*(ez_inc(j)-ez_inc(j+1));
Pth4_]US
end;
g>eWX*Pa|
G`&P|xYg
%% 入射磁场傅里叶变换
k6GQH@y!
inh=inh+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hx_inc(ja-1);
AE`UnlUSF
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
/v|b]Ji
%% 磁场Hx
Ov4 [gHy&
for i=1:N;
}H saJ=1U
for j=1:N-1;
2']0c z
curl_e=ez(i,j)-ez(i,j+1);
Xc^(e?L4
ihx(i,j)=ihx(i,j)+fi1(i)*curl_e;
*CAz_s<
hx(i,j)=fj3(j)*hx(i,j)+fj2(j)*0.5*(curl_e+ihx(i,j));
e=IbEm{|
end;
X56q,jCJ{
end;
[u J<]
TiZ MY:^
%% 磁场Hx加入射场
:_2:Fh.}3~
for i=ia:ib;
)8n?.keq
hx(i,ja-1)=hx(i,ja-1)+0.5*ez_inc(ja);
zlTLp-^Y
hx(i,jb)=hx(i,jb)-0.5*ez_inc(jb);
_ouZd.
end;
<{hB&4oL
o8IqO'
% 傅里叶变换Hx;
B#.xs>{N
s=0;
AW9%E/{
% 注意:电场和磁场相差半个时间步
YcR: _ac
for i=pa:pb;
<7B;_3/
s=s+1;
4ji'6JHPg
hx_out(1,s)=hx_out(1,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hx(i,qa); % 下
3m2y<l<
hx_out(2,s)=hx_out(2,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hx(i,qb); % 上
pU,\ &3N
end;
,I+O;B:0
s=0;
3-n&&<
for j=qa:qb;
xB?!nd
s=s+1;
.i*ja*
hx_out(3,s)=hx_out(3,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hx(pa,j); % 左
QwF.c28[
hx_out(4,s)=hx_out(4,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hx(pb,j); % 右
u`oJ3mS;
end;
D&@ js!|5
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[nX{sM%
%% 磁场Hy
f,LeJTX=
for i=1:N-1;
p)"EenUK
for j=1:N;
gvo5^O+)HH
curl_e=ez(i+1,j)-ez(i,j);
0"+QWh
ihy(i,j)=ihy(i,j)+fj1(j)*curl_e;
^h#A7 g
hy(i,j)=fi3(i)*hy(i,j)+fi2(i)*0.5*(curl_e+ihy(i,j));
%u<r_^w5
end;
#)#'^MZX
end;
;j(*:Nt1
l^o>7 cM
%% 磁场Hy加入射场
D62'bFB^
for j=ja:jb;
W~i0.rg|>
hy(ia-1,j)=hy(ia-1,j)-0.5*ez_inc(j);
jv1p'qs4
hy(ib,j)=hy(ib,j)+0.5*ez_inc(j);
~x_(v,NW
end;
;ByCtVm2
5GPAt
% 傅里叶变换Hy;
<5CQ#^cK
s=0;
5H 1x-b
for i=pa:pb;
9o6qN1A0g
s=s+1;
Et}%sdS
hy_out(1,s)=hy_out(1,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hy(i,qa); % 下
/BF7N3
hy_out(2,s)=hy_out(2,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hy(i,qb); % 上
^{++h?cS)
end;
L;b-=mF
s=0;
2"P1I
for j=qa:qb;
$U. 2"
s=s+1;
~{kA;uw
hy_out(3,s)=hy_out(3,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hy(pa,j); % 左
_+}hId
hy_out(4,s)=hy_out(4,s)+exp(-sqrt(-1)*2*pi*f*(T+1/2)*dt)*hy(pb,j); % 右
W&Xi&[Ux
end;
P/]8+_K
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
A^0-%Ygl
% 显示
C)9-{Yp
plot(hx(40,:));
4xFAFK~lx
Yx ;j
mesh(ez)
q?L*Luu+
axis([1 120 1 120 -0.5 0.5]);
Ml+f3#HP
drawnow;
XoMgbDC
end;
@e7_&EGR?
Z vyF"4QN
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
&;GoCU Le
% %%****************************近远场外推**********************************%%
*S4&V<W>
%
X\<a|/{V A
%% 电场平均
Y!|};
for i=1:length
`<Hc,D; p
ez_outave(:,i)=(ez_out(:,i)+ez_out(:,i+1))/2;
2Y=Q%
end
#}Ays#wA>?
=umF C[.W
current=zeros(4,length); % 电流z方向
mcQ\"9 ;pY
magnetic_x=zeros(4,length); % 磁流x方向
+OB&PE
magnetic_y=zeros(4,length); % 磁流y方向
[!ZYtp?Hf
}JT&lyO< b
%% 电流z
4L,&a+)
current(1,:)=hx_out(1,:); % 下
+yHzp
current(2,:)=-hx_out(2,:); % 上
H-X5A\\5
current(3,:)=-hy_out(3,:); % 左
R9+f^o`W
current(4,:)=hy_out(4,:); % 右
:b#5cMUe
}ASBP:c"t
%% 磁流x
kll,^A
magnetic_x(1,:)=ez_outave(1,:); % 下
jd 8g0^
magnetic_x(2,:)=-ez_outave(2,:); % 上
MUN:}S
magnetic_x(3,:)=0; % 左
xelh!AtE
magnetic_x(4,:)=0; % 右
u/\Ipk/
d{C8}U
%% 磁流y
~H]d9C
magnetic_y(1,:)=0; % 下
(hv}K*c{
magnetic_y(2,:)=0; % 上
_tO2PIL@Z
magnetic_y(3,:)=-ez_outave(3,:); % 左
3|Ar~_]
magnetic_y(4,:)=ez_outave(4,:); % 右
DFGgyFay
tfe'].uT
%% 外推边界坐标X,Y
kYd=DY
posx=zeros(4,length);
?C6`
posy=zeros(4,length);
T(~^X-k
[Kbna>`
posx(1,:)=linspace(pa*ddx,pb*ddx,length)+ddx/2; % 下
BMhuM~?(
posx(2,:)=linspace(pa*ddx,pb*ddx,length)+ddx/2; % 上
6b!1j,\Vx
posx(3,:)=pa*ddx; % 左
H"2,Q T
posx(4,:)=pb*ddx; % 右
I+Fr#1
\nQEvcH
posy(1,:)=qa*ddx; % 下
`]Vn[^?D
posy(2,:)=qb*ddx; % 上
,l\D@<F
posy(3,:)=linspace(qa*ddx,qb*ddx,length)+ddx/2; % 左
o%Qn%gaX
posy(4,:)=linspace(qa*ddx,qb*ddx,length)+ddx/2; % 右
V<REcII.
a1weTn*
%% 归一化fz,fmx,fmy求解
m :]F&s
fz=ddx*current/abs(inh);
2Ju,P_<dt
fmx=ddx*magnetic_x/abs(inh);
D[Ld=e8t
fmy=ddx*magnetic_y/abs(inh);
_&xkj8O
YeF'r.Y
%% RCS求解;
{Z[kvXf"mZ
co=0;
%';DBozZ
for phi=pi/2:pi/180:pi+pi/2;
6(HJYa
co=co+1;
`7',RUj|D
ss=0;
8[8U49V9(
for t=1:4;
MpJx>0j/J
for s=1:length
!|Y&h0e
kr=posx(t,s)*cos(phi)+posy(t,s)*sin(phi);
HsK52<
ss=ss+(-fz(t,s)-fmx(t,s)*sin(phi)+fmy(t,s)*cos(phi))*exp(sqrt(-1)*k*kr); %% 外推公式
['0^gN$:e
end
eA/}$.R
end;
'FN3r
rcs(co)=k/4*(abs(ss)).^2;
+OUM 4y
end;
=E8Kacu%
rcs=10*log10(rcs/(lamda));
Zo,]Dx
save fdtdupml rcs;
jg3['hTJT
figure(2)
yhyh\.
plot(rcs,'g');
D/WzYc2h]
.fY$$aD$4
rcs_upml=rcs;
W8!8/IZbN
save rcs_upml.mat rcs_upml;
q{)Q ?E
7|?Ht]
toc;
+ V-&?E(
% hold on;
ra\|c>[%
Szlww
那位能告诉我红色的那段程序用的是什么公式吗?为什么总是看不懂,还有0.5是哪边来的,谢谢各位留言。。
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gwzhao
方恨少
UID :17098
注册:
2008-08-24
登录:
2019-01-09
发帖:
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荣誉管理员
2楼
发表于: 2009-05-06 11:12:17
for j=2:N-1;
zKk2>.
ez_inc(j)=ez_inc(j)+0.5*(hx_inc(j-1)-hx_inc(j));
_\LAWQ|M4[
end;
&6L{1
for j=1:N-1;
w#,C{6
hx_inc(j)=hx_inc(j)+0.5*(ez_inc(j)-ez_inc(j+1));
zW^@\kB0D
end;
<[7.+{qfW
bmO[9 )G
这个是1D FDTD来模拟平面波的,你随便找个FDTD的书,看一下1D FDTD的简单例子就明白了。
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alai318
rf币
+5
感谢您的资料
2009-05-06
逆流而上
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flanky
UID :19721
注册:
2008-10-21
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2011-11-15
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仿真一级
3楼
发表于: 2009-05-06 18:03:22
谢谢楼上的。。
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cem-uestc
UID :9061
注册:
2008-03-07
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2019-01-05
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4楼
发表于: 2009-05-07 14:14:12
对应书上来分析代码,是最好的学习FDTD方式
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欢迎光临
http://www.mwtee.com/home.php?mod=space&uid=13535
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tapioca
UID :73610
注册:
2011-03-11
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2012-04-29
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仿真新人
5楼
发表于: 2011-06-03 16:49:02
有木有人知道斜入射怎么仿真啊。。。一维波的斜入射打到海平面。。。FDTD网格怎么设置呢
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gwzhao
方恨少
UID :17098
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2008-08-24
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6楼
发表于: 2011-06-06 21:16:47
回 5楼(tapioca) 的帖子
论坛里有很多类似问题的帖子,你可以找找看。
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逆流而上
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jiandan1986
UID :77042
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2011-05-09
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仿真新人
7楼
发表于: 2011-06-09 21:04:49
dz应该是对应的系数,在使用中心差分时定义的。
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