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
147
148
149
150
151
152
153
154
|
close all
clear
clc
%% setup the simulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
feed_length=10;
wire_rad = sqrt(1.4/pi);
mesh_size = wire_rad;
coil_rad = 10;
coil_length = 50;
coil_turns = 8;
coil_res = 10;
port_length = mesh_size; %coil_length/2;
port_resist = 1000;
f_max = 100e6;
f_excite = 300e6;
%% define openEMS options %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
openEMS_opts = '';
% openEMS_opts = [openEMS_opts ' --debug-material'];
% openEMS_opts = [openEMS_opts ' --debug-boxes'];
% openEMS_opts = [openEMS_opts ' --debug-operator'];
openEMS_opts = [openEMS_opts ' --disable-dumps --engine=fastest'];
% openEMS_opts = [openEMS_opts ' --engine=sse-compressed'];
Sim_Path = 'tmp';
Sim_CSX = 'helix.xml';
[status, message, messageid] = rmdir(Sim_Path,'s');
[status,message,messageid] = mkdir(Sim_Path);
%% setup FDTD parameter & excitation function %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FDTD = InitFDTD(30000,1e-6);
FDTD = SetGaussExcite(FDTD,f_excite/2,f_excite/2);
BC = [1 1 1 1 1 1];
FDTD = SetBoundaryCond(FDTD,BC);
%% setup CSXCAD geometry & mesh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
add_Lines = mesh_size * 1.5.^(1:10);
add_Lines = add_Lines(find(add_Lines<(3e8/f_excite)/10*1e3));
CSX = InitCSX();
mesh.x = -coil_rad-mesh_size : mesh_size : coil_rad+mesh_size+feed_length;
mesh.x = [mesh.x(1)-add_Lines mesh.x mesh.x(end)+add_Lines ];
mesh.y = -coil_rad-mesh_size : mesh_size : coil_rad+mesh_size;
mesh.y = [mesh.y(1)-add_Lines mesh.y mesh.y(end)+add_Lines ];
mesh.z = -mesh_size : mesh_size : coil_length+mesh_size;
mesh.z = [mesh.z(1)-add_Lines mesh.z mesh.z(end)+add_Lines ];
CSX = DefineRectGrid(CSX, 1e-3,mesh);
%% build/define helix %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CSX = AddMaterial(CSX,'copper');
CSX = SetMaterialProperty(CSX,'copper','Kappa',56e6);
dt = 1.0/coil_res;
height=0;
wire.Vertex = {};
p(1,1) = coil_rad + feed_length;
p(2,1) = 0;
p(3,1) = 0.5*(coil_length-port_length);
p(1,2) = coil_rad + feed_length;
p(2,2) = 0;
p(3,2) = 0;
count=2;
for n=0:coil_turns-1
for m=0:coil_res
count = count + 1;
p(1,count) = coil_rad * cos(2*pi*dt*m);
p(2,count) = coil_rad * sin(2*pi*dt*m);
p(3,count) = height + coil_length/coil_turns * dt*m;
end
height = height + coil_length/coil_turns;
end
p(1,count+1) = coil_rad + feed_length;
p(2,count+1) = 0;
p(3,count+1) = coil_length;
p(1,count+2) = coil_rad + feed_length;
p(2,count+2) = 0;
p(3,count+2) = 0.5*(coil_length+port_length);
CSX = AddWire(CSX, 'copper', 0, p, wire_rad);
%% apply the excitation & resist as a current source%%%%%%%%%%%%%%%%%%%%%%%
CSX = AddMaterial(CSX,'resist');
kappa = port_length/port_resist/wire_rad^2/pi/1e-3;
CSX = SetMaterialProperty(CSX,'resist','Kappa',kappa);
start=[coil_rad+feed_length 0 (coil_length-port_length)/2];
stop=[coil_rad+feed_length 0 (coil_length+port_length)/2];
%start(3)=(coil_length-port_length)/2;stop(3)=(coil_length+port_length)/2;
CSX = AddCylinder(CSX,'resist',5 ,start,stop,wire_rad);
CSX = AddExcitation(CSX,'excite',0,[0 0 1]);
CSX = AddCylinder(CSX,'excite', 0 ,start,stop,wire_rad);
%% define voltage calc boxes %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%voltage calc
CSX = AddProbe(CSX,'ut1',0);
CSX = AddBox(CSX,'ut1', 0 ,stop,start);
%current calc
CSX = AddProbe(CSX,'it1',1);
start(3) = coil_length/2+mesh_size;stop(3) = coil_length/2+mesh_size;
start(1) = start(1)-2;start(2) = start(2)-2;
stop(1) = stop(1)+2;stop(2) = stop(2)+2;
CSX = AddBox(CSX,'it1', 0 ,start,stop);
%% define dump boxes... %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CSX = AddDump(CSX,'Et_');
start = [mesh.x(1) , 0 , mesh.z(1)];
stop = [mesh.x(end) , 0 , mesh.z(end)];
CSX = AddBox(CSX,'Et_',0 , start,stop);
CSX = AddDump(CSX,'Ht_','DumpType',1);
start = [mesh.x(1) , 0 , mesh.z(1)];
stop = [mesh.x(end) , 0 , mesh.z(end)];
CSX = AddBox(CSX,'Ht_',0 , start,stop);
%% Write openEMS compatoble xml-file %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
WriteOpenEMS([Sim_Path '/' Sim_CSX],FDTD,CSX);
%% run openEMS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
RunOpenEMS(Sim_Path, Sim_CSX, openEMS_opts);
%% postproc & do the plots %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
U = ReadUI('ut1','tmp/');
I = ReadUI('it1','tmp/');
Z = U.FD{1}.val./I.FD{1}.val;
f = U.FD{1}.f;
L = imag(Z)./(f*2*pi);
R = real(Z);
ind = find(f<f_max);
subplot(2,1,1);
plot(f(ind)*1e-6,L(ind)*1e9,'Linewidth',2);
xlabel('frequency (MHz)');
ylabel('coil inductance (nH)');
grid on;
subplot(2,1,2);
plot(f(ind)*1e-6,R(ind),'Linewidth',2);
hold on
plot(f(ind)*1e-6,imag(Z(ind)),'r','Linewidth',2);
xlabel('frequency (MHz)');
ylabel('resistance (Ohm)');
grid on;
legend( {'real','imaginary'}, 'location', 'northwest' )
figure
plot(U.TD{1}.t/1e-6,U.TD{1}.val,'Linewidth',2);
xlabel('time (us)');
ylabel('amplitude (V)');
grid on;
|
