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Diffstat (limited to 'openEMS/matlab/Tutorials/Rect_Waveguide.m')
-rw-r--r-- | openEMS/matlab/Tutorials/Rect_Waveguide.m | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/openEMS/matlab/Tutorials/Rect_Waveguide.m b/openEMS/matlab/Tutorials/Rect_Waveguide.m new file mode 100644 index 0000000..3b1a79a --- /dev/null +++ b/openEMS/matlab/Tutorials/Rect_Waveguide.m @@ -0,0 +1,121 @@ +% +% Tutorials / Rect_Waveguide +% +% Describtion at: +% http://openems.de/index.php/Tutorial:_Rectangular_Waveguide +% +% Tested with +% - Octave 4.0.0 +% - openEMS v0.0.33 +% +% (C) 2010-2015 Thorsten Liebig <thorsten.liebig@gmx.de> + +close all +clear +clc + +%% setup the simulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +physical_constants; +unit = 1e-6; %drawing unit in um + +% waveguide dimensions +% WR42 +a = 10700; %waveguide width +b = 4300; %waveguide heigth +length = 50000; + +% frequency range of interest +f_start = 20e9; +f_0 = 24e9; +f_stop = 26e9; +lambda0 = c0/f_0/unit; + +%waveguide TE-mode definition +TE_mode = 'TE10'; + +%targeted mesh resolution +mesh_res = lambda0./[30 30 30]; + +%% setup FDTD parameter & excitation function %%%%%%%%%%%%%%%%%%%%%%%%%%%%% +FDTD = InitFDTD('NrTS',1e4, 'OverSampling', 5); +FDTD = SetGaussExcite(FDTD,0.5*(f_start+f_stop),0.5*(f_stop-f_start)); + +% boundary conditions +BC = [0 0 0 0 3 3]; %pml in pos. and neg. z-direction +FDTD = SetBoundaryCond(FDTD,BC); + +%% setup CSXCAD mesh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +CSX = InitCSX(); +mesh.x = SmoothMeshLines([0 a], mesh_res(1)); +mesh.y = SmoothMeshLines([0 b], mesh_res(2)); +mesh.z = SmoothMeshLines([0 length], mesh_res(3)); +CSX = DefineRectGrid(CSX, unit,mesh); + +%% apply the waveguide port %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +start=[mesh.x(1) mesh.y(1) mesh.z(11)]; +stop =[mesh.x(end) mesh.y(end) mesh.z(15)]; +[CSX, port{1}] = AddRectWaveGuidePort( CSX, 0, 1, start, stop, 'z', a*unit, b*unit, TE_mode, 1); + +start=[mesh.x(1) mesh.y(1) mesh.z(end-13)]; +stop =[mesh.x(end) mesh.y(end) mesh.z(end-14)]; +[CSX, port{2}] = AddRectWaveGuidePort( CSX, 0, 2, start, stop, 'z', a*unit, b*unit, TE_mode); + +%% define dump box... %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +CSX = AddDump(CSX,'Et','FileType',1,'SubSampling','2,2,2'); +start = [mesh.x(1) mesh.y(1) mesh.z(1)]; +stop = [mesh.x(end) mesh.y(end) mesh.z(end)]; +CSX = AddBox(CSX,'Et',0 , start,stop); + +%% Write openEMS compatoble xml-file %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +Sim_Path = 'tmp_mod'; +Sim_CSX = 'rect_wg.xml'; + +[status, message, messageid] = rmdir(Sim_Path,'s'); +[status, message, messageid] = mkdir(Sim_Path); + +WriteOpenEMS([Sim_Path '/' Sim_CSX],FDTD,CSX); + +RunOpenEMS(Sim_Path, Sim_CSX) + +%% postproc %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +freq = linspace(f_start,f_stop,201); +port = calcPort(port, Sim_Path, freq); + +s11 = port{1}.uf.ref./ port{1}.uf.inc; +s21 = port{2}.uf.ref./ port{1}.uf.inc; +ZL = port{1}.uf.tot./port{1}.if.tot; +ZL_a = port{1}.ZL; % analytic waveguide impedance + +%% plot s-parameter %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +figure +plot(freq*1e-6,20*log10(abs(s11)),'k-','Linewidth',2); +xlim([freq(1) freq(end)]*1e-6); +grid on; +hold on; +plot(freq*1e-6,20*log10(abs(s21)),'r--','Linewidth',2); +l = legend('S_{11}','S_{21}','Location','Best'); +set(l,'FontSize',12); +ylabel('S-Parameter (dB)','FontSize',12); +xlabel('frequency (MHz) \rightarrow','FontSize',12); + +%% compare analytic and numerical wave-impedance %%%%%%%%%%%%%%%%%%%%%%%%%% +figure +plot(freq*1e-6,real(ZL),'Linewidth',2); +hold on; +grid on; +plot(freq*1e-6,imag(ZL),'r--','Linewidth',2); +plot(freq*1e-6,ZL_a,'g-.','Linewidth',2); +ylabel('ZL (\Omega)','FontSize',12); +xlabel('frequency (MHz) \rightarrow','FontSize',12); +xlim([freq(1) freq(end)]*1e-6); +l = legend('\Re(Z_L)','\Im(Z_L)','Z_L analytic','Location','Best'); +set(l,'FontSize',12); + +%% Plot the field dumps %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +figure +dump_file = [Sim_Path '/Et.h5']; +PlotArgs.slice = {a/2*unit b/2*unit 0}; +PlotArgs.pauseTime=0.01; +PlotArgs.component=0; +PlotArgs.Limit = 'auto'; +PlotHDF5FieldData(dump_file, PlotArgs) |