131 lines
3.6 KiB
Matlab
131 lines
3.6 KiB
Matlab
close all;
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clear all;
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clc
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EPS0 = 8.85418781762e-12;
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MUE0 = 1.256637062e-6;
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C0 = 1/sqrt(EPS0*MUE0);
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Z0 = sqrt(MUE0/EPS0);
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f0 = 0.5e9;
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epsR = 3.6;
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abs_length = 250;
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length = 6000;
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port_dist = 1500;
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rad_i = 100;
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rad_a = 230;
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partial = 0.25;
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max_mesh = 10;
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max_alpha = max_mesh;
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N_alpha = ceil(rad_a * 2*pi * partial / max_alpha);
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mesh_res = [max_mesh 2*pi*partial/N_alpha max_mesh];
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openEMS_Path = [pwd() '/../../']
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openEMS_opts = '';
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openEMS_opts = [openEMS_opts ' --disable-dumps'];
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% openEMS_opts = [openEMS_opts ' --debug-material'];
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Sim_Path = 'tmp';
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Sim_CSX = 'coax.xml';
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mkdir(Sim_Path);
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%setup FDTD parameter
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FDTD = InitCylindricalFDTD(1e5,1e-5);
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FDTD = SetGaussExcite(FDTD,f0,f0);
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BC = [0 0 1 1 0 0];
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FDTD = SetBoundaryCond(FDTD,BC);
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%setup CSXCAD geometry
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CSX = InitCSX();
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mesh.x = rad_i : mesh_res(1) : rad_a;
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mesh.y = -pi*partial-mesh_res(2)/2 : mesh_res(2) : pi*partial+mesh_res(2)/2;
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mesh.z = 0 : mesh_res(3) : length;
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CSX = DefineRectGrid(CSX, 1e-3,mesh);
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%%%fake pml
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finalKappa = 0.3/abs_length^4;
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finalSigma = finalKappa*MUE0/EPS0/epsR;
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CSX = AddMaterial(CSX,'pml');
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CSX = SetMaterialProperty(CSX,'pml','Kappa',finalKappa,'Epsilon',epsR);
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CSX = SetMaterialProperty(CSX,'pml','Sigma',finalSigma);
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CSX = SetMaterialWeight(CSX,'pml','Kappa',['pow(abs(z)-' num2str(length-abs_length) ',4)']);
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CSX = SetMaterialWeight(CSX,'pml','Sigma',['pow(abs(z)-' num2str(length-abs_length) ',4)']);
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start = [rad_i mesh.y(1) length-abs_length];
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stop = [rad_a mesh.y(end) length];
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CSX = AddBox(CSX,'pml',0 ,start,stop);
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CSX = AddMaterial(CSX,'fill');
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CSX = SetMaterialProperty(CSX,'fill','Epsilon',epsR);
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start = [mesh.x(1) mesh.y(1) 0];
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stop = [mesh.x(end) mesh.y(end) length];
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CSX = AddBox(CSX,'fill',0 ,start,stop);
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start = [rad_i mesh.y(1) 0];
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stop = [rad_a mesh.y(end) 0];
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CSX = AddExcitation(CSX,'excite',0,[1 0 0]);
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weight{1} = '1/rho';
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weight{2} = 0;
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weight{3} = 0;
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CSX = SetExcitationWeight(CSX, 'excite', weight );
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CSX = AddBox(CSX,'excite',0 ,start,stop);
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%dump
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CSX = AddDump(CSX,'Et_','DumpMode',2);
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start = [mesh.x(1) , 0 , mesh.z(1)];
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stop = [mesh.x(end) , 0 , mesh.z(end)];
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CSX = AddBox(CSX,'Et_',0 , start,stop);
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CSX = AddDump(CSX,'Ht_','DumpType',1,'DumpMode',2);
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CSX = AddBox(CSX,'Ht_',0,start,stop);
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% voltage calc (take a voltage average to be at the same spot as the
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% current calculation)
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CSX = AddProbe(CSX,'ut1_1',0);
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start = [ rad_i 0 port_dist ];stop = [ rad_a 0 port_dist ];
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CSX = AddBox(CSX,'ut1_1', 0 ,start,stop);
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CSX = AddProbe(CSX,'ut1_2',0);
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start = [ rad_i 0 port_dist+mesh_res(3) ];stop = [ rad_a 0 port_dist+mesh_res(3) ];
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CSX = AddBox(CSX,'ut1_2', 0 ,start,stop);
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% current calc
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CSX = AddProbe(CSX,'it1',1);
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mid = 0.5*(rad_i+rad_a);
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start = [ 0 mesh.y(1) port_dist ];stop = [ mid mesh.y(end) port_dist ];
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CSX = AddBox(CSX,'it1', 0 ,start,stop);
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%Write openEMS compatoble xml-file
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WriteOpenEMS([Sim_Path '/' Sim_CSX],FDTD,CSX);
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%cd to working dir and run openEMS
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savePath = pwd();
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cd(Sim_Path); %cd to working dir
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command = [openEMS_Path 'openEMS.sh ' Sim_CSX ' ' openEMS_opts];
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disp(command);
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system(command)
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cd(savePath);
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UI = ReadUI({'ut1_1','ut1_2','it1'},'tmp/');
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u_f = (UI.FD{1}.val + UI.FD{2}.val)/2; %averaging voltages to fit current
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i_f = UI.FD{3}.val / partial;
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delta_t = UI.TD{3}.t(1) - UI.TD{1}.t(1); % half time-step (s)
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i_f2 = i_f .* exp(-1i*2*pi*UI.FD{1}.f*delta_t); % compensate half time-step advance of H-field
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ZL = Z0/2/pi/sqrt(epsR)*log(rad_a/rad_i); %analytic line-impedance of a coax
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plot(UI.FD{1}.f,ZL*ones(size(u_f)),'g');
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hold on;
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grid on;
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Z = u_f./i_f2;
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plot(UI.FD{1}.f,real(Z),'Linewidth',2);
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plot(UI.FD{1}.f,imag(Z),'r','Linewidth',2);
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xlim([0 2*f0]);
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legend('Z_L','\Re\{Z\}','\Im\{Z\}','Location','Best');
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