157 lines
4.6 KiB
Matlab
157 lines
4.6 KiB
Matlab
close all
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clear
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clc
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%% setup the simulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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length = 2000;
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unit = 1e-3;
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a = 1000;
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width = a;
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b = 500;
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height = b;
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mesh_res = [10 10 10];
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%define mode
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m = 1;
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n = 0;
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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 = 1e9;
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freq = linspace(f0-f0/3,f0+f0/3,201);
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k = 2*pi*freq/C0;
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kc = sqrt((m*pi/a/unit)^2 + (n*pi/b/unit)^2);
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fc = C0*kc/2/pi;
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beta = sqrt(k.^2 - kc^2);
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ZL_a = k * Z0 ./ beta;
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%% mode functions %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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func_Ex = [num2str( n/b/unit) '*cos(' num2str(m*pi/a) '*x)*sin(' num2str(n*pi/b) '*y)'];
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func_Ey = [num2str(-m/a/unit) '*sin(' num2str(m*pi/a) '*x)*cos(' num2str(n*pi/b) '*y)'];
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func_Hx = [num2str(m/a/unit) '*sin(' num2str(m*pi/a) '*x)*cos(' num2str(n*pi/b) '*y)'];
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func_Hy = [num2str(n/b/unit) '*cos(' num2str(m*pi/a) '*x)*sin(' num2str(n*pi/b) '*y)'];
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%% define and openEMS options %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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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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openEMS_opts = [openEMS_opts ' --engine=fastest'];
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Settings = [];
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Settings.LogFile = 'openEMS.log';
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Sim_Path = 'tmp';
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Sim_CSX = 'rect_wg.xml';
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if (exist(Sim_Path,'dir'))
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rmdir(Sim_Path,'s');
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end
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mkdir(Sim_Path);
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%% setup FDTD parameter & excitation function %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FDTD = InitFDTD(50000,1e-5,'OverSampling',6);
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FDTD = SetGaussExcite(FDTD,f0,f0/3);
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BC = [0 0 0 0 0 3];
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FDTD = SetBoundaryCond(FDTD,BC);
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%% setup CSXCAD geometry & mesh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CSX = InitCSX();
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mesh.x = 0 : mesh_res(1) : width;
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mesh.y = 0 : mesh_res(2) : height;
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mesh.z = 0 : mesh_res(3) : length;
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CSX = DefineRectGrid(CSX, unit,mesh);
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%% apply the excitation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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start=[0 0 mesh.z(1) ];
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stop =[width height mesh.z(1) ];
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CSX = AddExcitation(CSX,'excite',0,[1 1 0]);
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weight{1} = func_Ex;
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weight{2} = func_Ey;
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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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%% voltage and current definitions using the mode matching probes %%%%%%%%%
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start = [mesh.x(1) mesh.y(1) mesh.z(15)];
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stop = [mesh.x(end) mesh.y(end) mesh.z(15)];
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CSX = AddProbe(CSX, 'ut1', 10, 1, [], 'ModeFunction',{func_Ex,func_Ey,0});
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CSX = AddBox(CSX, 'ut1', 0 ,start,stop);
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CSX = AddProbe(CSX,'it1', 11, 1, [], 'ModeFunction',{func_Hx,func_Hy,0});
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CSX = AddBox(CSX,'it1', 0 ,start,stop);
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start = [mesh.x(1) mesh.y(1) mesh.z(end-15)];
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stop = [mesh.x(end) mesh.y(end) mesh.z(end-15)];
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CSX = AddProbe(CSX, 'ut2', 10, 1, [], 'ModeFunction',{func_Ex,func_Ey,0});
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CSX = AddBox(CSX, 'ut2', 0 ,start,stop);
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CSX = AddProbe(CSX,'it2', 11, 1, [], 'ModeFunction',{func_Hx,func_Hy,0});
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CSX = AddBox(CSX,'it2', 0 ,start,stop);
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%% define dump boxes... %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CSX = AddDump(CSX,'Et','FileType',1,'SubSampling','4,4,2');
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start = [mesh.x(1) , height/2 , mesh.z(1)];
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stop = [mesh.x(end) , height/2 , mesh.z(end)];
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CSX = AddBox(CSX,'Et',0 , start,stop);
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CSX = AddDump(CSX,'Ht','DumpType',1,'FileType',1,'SubSampling','4,4,2');
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CSX = AddBox(CSX,'Ht',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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RunOpenEMS(Sim_Path, Sim_CSX, openEMS_opts, Settings)
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%% postproc %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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U = ReadUI({'ut1','ut2'},[Sim_Path '/'],freq);
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I = ReadUI({'it1','it2'},[Sim_Path '/'],freq);
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Exc = ReadUI('et',Sim_Path,freq);
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uf1 = U.FD{1}.val./Exc.FD{1}.val;
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uf2 = U.FD{2}.val./Exc.FD{1}.val;
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if1 = I.FD{1}.val./Exc.FD{1}.val;
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if2 = I.FD{2}.val./Exc.FD{1}.val;
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uf1_inc = 0.5 * ( uf1 + if1 .* ZL_a );
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if1_inc = 0.5 * ( if1 + uf1 ./ ZL_a );
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uf2_inc = 0.5 * ( uf2 + if2 .* ZL_a );
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if2_inc = 0.5 * ( if2 + uf2 ./ ZL_a );
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uf1_ref = uf1 - uf1_inc;
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if1_ref = if1 - if1_inc;
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uf2_ref = uf2 - uf2_inc;
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if2_ref = if2 - if2_inc;
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%% plot s-parameter
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figure
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s11 = uf1_ref./uf1_inc;
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s21 = uf2_inc./uf1_inc;
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plot(freq,20*log10(abs(s11)),'Linewidth',2);
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xlim([freq(1) freq(end)]);
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% ylim([-40 5]);
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grid on;
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hold on;
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plot(freq,20*log10(abs(s21)),'r','Linewidth',2);
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legend('s11','s21','Location','SouthEast');
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ylabel('s-para (dB)');
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xlabel('freq (Hz)');
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%% compare analytic and numerical wave-impedance
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ZL = uf1./if1;
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figure()
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plot(freq,real(ZL),'Linewidth',2);
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hold on;
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grid on;
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plot(freq,imag(ZL),'r--','Linewidth',2);
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plot(freq,ZL_a,'g-.','Linewidth',2);
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ylabel('ZL (\Omega)');
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xlabel('freq (Hz)');
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xlim([freq(1) freq(end)]);
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legend('\Re(Z_L)','\Im(Z_L)','Z_L analytic','Location','Best');
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