forked from overengineer/TR-FDTD
-
Notifications
You must be signed in to change notification settings - Fork 0
/
diel_no_tumor_lin.m
146 lines (131 loc) · 3.74 KB
/
diel_no_tumor_lin.m
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
%physical constants
clear all;
close all;
c0 = 2.998e8;
eta0 = 120*pi;
mu0 = pi*4e-7;
eps0 = 1e-9/(36*pi);
%box dimensions
width = 0.5; % cm
height = 0.5;
length = 0.5; % cm
%source parameters
f0 = 1e9; % GHz
band = 2e9;
tw = sqrt(-log(0.1)/(pi*band)^2);%1e-8/pi;
t0 = 4*tw;
%spatial discretization
adipose = 1; %5;
sigma = 0;
epsr = 10;
w = 2 * pi * band;
k = (w/c0)*sqrt(epsr-1j*sigma/(w*eps0));
beta = real(k);
c = w / beta;
lambda = c/f0;
dxmax = lambda / 20;
dx = dxmax;
dy = dxmax;
dz = dxmax;
nx = round(width/dx);
ny = round(height/dy);
nz = round(length/dz);
%source position
srcx = round(nx / 2);
srcy = round( 3 * ny / 4);
srcz = round(nz / 2);
%material
al = 0;
eps = ones(nx,ny,nz) * eps0 ;
sigma = zeros(nx,ny,nz);%*f0 * 1e-9 * 0.5 - 0.5;
for i=1:1:nx
for j=1:1:ny
for k=1:1:nz
% adipose tissue is located under z < al
if (k<al)
eps(i,j,k) = eps0 * adipose;
sigma(i,j,k) = 0;
end
end
end
end
%time discretization
dt = 0.99/(c0*sqrt(dx^-2+dy^-2+dz^-2));
tw=16*dt;
t0=3*tw;
n_iter = 250;
%receivers
nrec = round(nx / 3)-1;
recdx = round(nx / nrec);
recy = srcy-15;
recz = srcz;
rec = zeros(nrec,n_iter);
%EM field dimensions
Hx = zeros(nx,ny,nz);
Hy = zeros(nx,ny,nz);
Hz = zeros(nx,ny,nz);
Ex = zeros(nx,ny,nz);
Ey = zeros(nx,ny,nz);
Ez = zeros(nx,ny,nz);
%iteration
i = 0;
for n=1:1:n_iter
%magnetic field derivatives
Hxy = diff(Hx,1,2);
Hxz = diff(Hx,1,3);
Hzx = diff(Hz,1,1);
Hzy = diff(Hz,1,2);
Hyx = diff(Hy,1,1);
Hyz = diff(Hy,1,3);
%electric field maxwell equations
epsi = eps(:,2:end-1,2:nz-1);
ksi = (dt * sigma(:,2:end-1,2:nz-1)) ./ ( 2 * epsi );
c2 = (1./(1+ksi)).*(dt./epsi);
c1 = (1-ksi)./(1+ksi);
Ex(:,2:end-1,2:end-1) = c1.*Ex(:,2:end-1,2:nz-1) + c2.*((1/dy)*Hzy(:,1:end-1,2:end-1) - (1/dz)*Hyz(:,2:ny-1,1:end-1));
epsi = eps(2:end-1,:,2:end-1);
ksi = (dt * sigma(2:end-1,:,2:end-1)) ./ ( 2 * epsi );
c2 = (1./(1+ksi)).*(dt./epsi);
c1 = (1-ksi)./(1+ksi);
Ey(2:end-1,:,2:end-1) = c1.*Ey(2:end-1,:,2:end-1) + c2.*((1/dz)*Hxz(2:end-1,:,1:end-1) - (1/dx)*Hzx(1:end-1,:,2:end-1));
epsi = eps(2:end-1,2:end-1,:);
ksi = (dt * sigma(2:end-1,2:end-1,:)) ./ ( 2 * epsi );
c2 = (1./(1+ksi)).*(dt./epsi);
c1 = (1-ksi)./(1+ksi);
Ez(2:end-1,2:end-1,:) = c1.*Ez(2:end-1,2:end-1,:) + c2.*((1/dx)*Hyx(1:end-1,2:end-1,:) - (1/dy)*Hxy(2:end-1,1:end-1,:));
%gaussian source
%f(n) = sin(2*pi*f0*n*dt)*exp(-(n*dt-t0)^2/(tw^2))/dy;
f(n) = -2*(n*dt-t0)/tw*exp(-(n*dt-t0)^2/(tw^2))/dy;
Ez(srcx,srcy,srcz) = Ez(srcx,srcy,srcz) + f(n);
%Ezn(n)=Ez(srcx,srcy,srcz);
%electric field derivatives
Exy = diff(Ex,1,2);
Exz = diff(Ex,1,3);
Ezx = diff(Ez,1,1);
Ezy = diff(Ez,1,2);
Eyx = diff(Ey,1,1);
Eyz = diff(Ey,1,3);
%magnetic field maxwell equations
Hx(:,1:end-1,1:end-1) = Hx(:,1:end-1,1:end-1) - (dt/(mu0*dy))*Ezy(:,:,1:end-1) + (dt/(mu0*dz))*Eyz(:,1:end-1,:);
Hy(1:end-1,:,1:end-1) = Hy(1:end-1,:,1:end-1) - (dt/(mu0*dz))*Exz(1:end-1,:,:) + (dt/(mu0*dx))*Ezx(:,:,1:end-1);
Hz(1:end-1,1:end-1,:) = Hz(1:end-1,1:end-1,:) - (dt/(mu0*dx))*Eyx(:,1:end-1,:) + (dt/(mu0*dy))*Exy(1:end-1,:,:);
for k=1:1:nrec
rec(k,n) = Ez(recdx * k, recy, recz);
end
%display
if (mod(i,5)==0)
slice(:,:)=Ez(:,:,srcz);
pcolor(slice');
colorbar;
shading interp
drawnow
end
i = i+1;
disp(i)
end
close all
hold on
for k=1:1:nrec
plot(rec(k,:))
end
save('withouttumor.mat','rec','nrec','n_iter','recy','recdx','recz')