From f204bc2723bfdaa5f4a7541fc61eb74fdf79844e Mon Sep 17 00:00:00 2001 From: Thorsten Liebig Date: Tue, 26 Oct 2010 08:30:35 +0200 Subject: [PATCH] Mode matching probe: fixed an error in HField interpolation Now also excluding the boundaries from the MM. Updated waveguide example: Rect_Waveguide.m Signed-off-by: Thorsten Liebig --- FDTD/processmodematch.cpp | 24 +++-- FDTD/processmodematch.h | 6 +- matlab/examples/waveguide/Rect_Waveguide.m | 100 ++++++++++++++++++--- 3 files changed, 105 insertions(+), 25 deletions(-) diff --git a/FDTD/processmodematch.cpp b/FDTD/processmodematch.cpp index 0239f97..5d73c1d 100644 --- a/FDTD/processmodematch.cpp +++ b/FDTD/processmodematch.cpp @@ -61,6 +61,12 @@ void ProcessModeMatch::InitProcess() stop[n]=help; } + //exclude boundaries from mode-matching + if (start[n]==0) + ++start[n]; + if (stop[n]==Op->GetNumberOfLines(n)-1) + --stop[n]; + if (stop[n]>start[n]) ++Dump_Dim; @@ -185,7 +191,7 @@ void ProcessModeMatch::SetFieldType(int type) cerr << "ProcessModeMatch::SetFieldType: Warning, unknown field type..." << endl; } -double ProcessModeMatch::GetField(int ny, unsigned int pos[3]) +double ProcessModeMatch::GetField(int ny, const unsigned int pos[3]) { if (m_ModeFieldType==0) return GetEField(ny,pos); @@ -194,7 +200,7 @@ double ProcessModeMatch::GetField(int ny, unsigned int pos[3]) return 0; } -double ProcessModeMatch::GetEField(int ny, unsigned int pos[3]) +double ProcessModeMatch::GetEField(int ny, const unsigned int pos[3]) { if ((pos[ny]==0) || (pos[ny]==Op->GetNumberOfLines(ny)-1)) return 0.0; @@ -210,7 +216,7 @@ double ProcessModeMatch::GetEField(int ny, unsigned int pos[3]) return 0.0; } -double ProcessModeMatch::GetHField(int ny, unsigned int pos[3]) +double ProcessModeMatch::GetHField(int ny, const unsigned int pos[3]) { if ((pos[ny]==0) || (pos[ny]>=Op->GetNumberOfLines(ny)-1)) return 0.0; @@ -218,19 +224,19 @@ double ProcessModeMatch::GetHField(int ny, unsigned int pos[3]) unsigned int EngPos[] = {pos[0],pos[1],pos[2]}; int nyP = (ny+1)%3; - if (pos[nyP] >= Op->GetNumberOfLines(nyP)-1) + if (pos[nyP] == 0) return 0.0; int nyPP = (ny+2)%3; - if (pos[nyPP] >= Op->GetNumberOfLines(nyPP)-1) + if (pos[nyPP] == 0) return 0.0; double hfield = Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); - EngPos[nyP]++; - hfield += Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); - EngPos[nyPP]++; - hfield += Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); EngPos[nyP]--; hfield += Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); + EngPos[nyPP]--; + hfield += Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); + EngPos[nyP]++; + hfield += Eng->GetCurr(ny,EngPos) / Op->GetMeshDelta(ny,EngPos,true); return hfield/4.0; } diff --git a/FDTD/processmodematch.h b/FDTD/processmodematch.h index 2a36e70..eae6665 100644 --- a/FDTD/processmodematch.h +++ b/FDTD/processmodematch.h @@ -43,9 +43,9 @@ protected: int m_ModeFieldType; - double GetField(int ny, unsigned int pos[3]); - double GetEField(int ny, unsigned int pos[3]); - double GetHField(int ny, unsigned int pos[3]); + double GetField(int ny, const unsigned int pos[3]); + double GetEField(int ny, const unsigned int pos[3]); + double GetHField(int ny, const unsigned int pos[3]); string m_ModeFunction[3]; CSFunctionParser* m_ModeParser[2]; diff --git a/matlab/examples/waveguide/Rect_Waveguide.m b/matlab/examples/waveguide/Rect_Waveguide.m index 8c27589..99d26a4 100644 --- a/matlab/examples/waveguide/Rect_Waveguide.m +++ b/matlab/examples/waveguide/Rect_Waveguide.m @@ -3,13 +3,13 @@ clear clc %% setup the simulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -length = 8000; +length = 2000; unit = 1e-3; a = 1000; width = a; b = 500; height = b; -mesh_res = [10 10 20]; +mesh_res = [10 10 10]; %define mode m = 1; @@ -18,16 +18,24 @@ n = 0; EPS0 = 8.85418781762e-12; MUE0 = 1.256637062e-6; C0 = 1/sqrt(EPS0*MUE0); +Z0 = sqrt(MUE0/EPS0); f0 = 1e9; +freq = linspace(f0-f0/3,f0+f0/3,201); -k = 2*pi*f0/C0; +k = 2*pi*freq/C0; kc = sqrt((m*pi/a/unit)^2 + (n*pi/b/unit)^2); fc = C0*kc/2/pi; -beta = sqrt(k^2 - kc^2); +beta = sqrt(k.^2 - kc^2); -func_Ex = [num2str(n/b/unit) '*cos(' num2str(m*pi/a) '*x)*sin(' num2str(n*pi/b) '*y)']; -func_Ey = [num2str(m/a/unit) '*sin(' num2str(m*pi/a) '*x)*cos(' num2str(n*pi/b) '*y)']; +ZL_a = k * Z0 ./ beta; + +%% mode functions %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +func_Ex = [num2str( n/b/unit) '*cos(' num2str(m*pi/a) '*x)*sin(' num2str(n*pi/b) '*y)']; +func_Ey = [num2str(-m/a/unit) '*sin(' num2str(m*pi/a) '*x)*cos(' num2str(n*pi/b) '*y)']; + +func_Hx = [num2str(m/a/unit) '*sin(' num2str(m*pi/a) '*x)*cos(' num2str(n*pi/b) '*y)']; +func_Hy = [num2str(n/b/unit) '*cos(' num2str(m*pi/a) '*x)*sin(' num2str(n*pi/b) '*y)']; %% define and openEMS options %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% openEMS_opts = ''; @@ -35,6 +43,9 @@ openEMS_opts = ''; % openEMS_opts = [openEMS_opts ' --debug-material']; openEMS_opts = [openEMS_opts ' --engine=fastest']; +Settings = []; +Settings.LogFile = 'openEMS.log'; + Sim_Path = 'tmp'; Sim_CSX = 'rect_wg.xml'; @@ -46,7 +57,7 @@ mkdir(Sim_Path); %% setup FDTD parameter & excitation function %%%%%%%%%%%%%%%%%%%%%%%%%%%%% FDTD = InitFDTD(50000,1e-5,'OverSampling',6); FDTD = SetGaussExcite(FDTD,f0,f0/3); -BC = [0 0 0 0 2 2]; +BC = [0 0 0 0 0 3]; FDTD = SetBoundaryCond(FDTD,BC); %% setup CSXCAD geometry & mesh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% @@ -57,26 +68,89 @@ mesh.z = 0 : mesh_res(3) : length; CSX = DefineRectGrid(CSX, unit,mesh); %% apply the excitation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -start=[0 0 mesh.z(3) ]; -stop =[width height mesh.z(3) ]; +start=[0 0 mesh.z(1) ]; +stop =[width height mesh.z(1) ]; CSX = AddExcitation(CSX,'excite',0,[1 1 0]); weight{1} = func_Ex; weight{2} = func_Ey; weight{3} = 0; CSX = SetExcitationWeight(CSX,'excite',weight); CSX = AddBox(CSX,'excite',0 ,start,stop); + +%% voltage and current definitions using the mode matching probes %%%%%%%%% +start = [mesh.x(1) mesh.y(1) mesh.z(15)]; +stop = [mesh.x(end) mesh.y(end) mesh.z(15)]; +CSX = AddProbe(CSX, 'ut1', 10, 1, [], 'ModeFunction',{func_Ex,func_Ey,0}); +CSX = AddBox(CSX, 'ut1', 0 ,start,stop); +CSX = AddProbe(CSX,'it1', 11, 1, [], 'ModeFunction',{func_Hx,func_Hy,0}); +CSX = AddBox(CSX,'it1', 0 ,start,stop); + +start = [mesh.x(1) mesh.y(1) mesh.z(end-15)]; +stop = [mesh.x(end) mesh.y(end) mesh.z(end-15)]; +CSX = AddProbe(CSX, 'ut2', 10, 1, [], 'ModeFunction',{func_Ex,func_Ey,0}); +CSX = AddBox(CSX, 'ut2', 0 ,start,stop); +CSX = AddProbe(CSX,'it2', 11, 1, [], 'ModeFunction',{func_Hx,func_Hy,0}); +CSX = AddBox(CSX,'it2', 0 ,start,stop); %% define dump boxes... %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -CSX = AddDump(CSX,'Et','FileType',0,'SubSampling','4,4,1'); +CSX = AddDump(CSX,'Et','FileType',1,'SubSampling','4,4,2'); start = [mesh.x(1) , height/2 , mesh.z(1)]; stop = [mesh.x(end) , height/2 , mesh.z(end)]; CSX = AddBox(CSX,'Et',0 , start,stop); -% CSX = AddDump(CSX,'Ht','DumpType',1,'FileType',1,'SubSampling','4,4,4'); -% CSX = AddBox(CSX,'Ht',0,start,stop); +CSX = AddDump(CSX,'Ht','DumpType',1,'FileType',1,'SubSampling','4,4,2'); +CSX = AddBox(CSX,'Ht',0,start,stop); %% Write openEMS compatoble xml-file %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% WriteOpenEMS([Sim_Path '/' Sim_CSX],FDTD,CSX); -RunOpenEMS(Sim_Path, Sim_CSX, openEMS_opts) +RunOpenEMS(Sim_Path, Sim_CSX, openEMS_opts, Settings) + + +%% postproc %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +U = ReadUI({'ut1','ut2'},[Sim_Path '/'],freq); +I = ReadUI({'it1','it2'},[Sim_Path '/'],freq); +Exc = ReadUI('et',Sim_Path,freq); + +uf1 = U.FD{1}.val./Exc.FD{1}.val; +uf2 = U.FD{2}.val./Exc.FD{1}.val; +if1 = I.FD{1}.val./Exc.FD{1}.val; +if2 = I.FD{2}.val./Exc.FD{1}.val; + +uf1_inc = 0.5 * ( uf1 + if1 .* ZL_a ); +if1_inc = 0.5 * ( if1 + uf1 ./ ZL_a ); +uf2_inc = 0.5 * ( uf2 + if2 .* ZL_a ); +if2_inc = 0.5 * ( if2 + uf2 ./ ZL_a ); + +uf1_ref = uf1 - uf1_inc; +if1_ref = if1 - if1_inc; +uf2_ref = uf2 - uf2_inc; +if2_ref = if2 - if2_inc; + +%% plot s-parameter +figure +s11 = uf1_ref./uf1_inc; +s21 = uf2_inc./uf1_inc; +plot(freq,20*log10(abs(s11)),'Linewidth',2); +xlim([freq(1) freq(end)]); +% ylim([-40 5]); +grid on; +hold on; +plot(freq,20*log10(abs(s21)),'r','Linewidth',2); +legend('s11','s21','Location','SouthEast'); +ylabel('s-para (dB)'); +xlabel('freq (Hz)'); + +%% compare analytic and numerical wave-impedance +ZL = uf1./if1; +figure() +plot(freq,real(ZL),'Linewidth',2); +hold on; +grid on; +plot(freq,imag(ZL),'r--','Linewidth',2); +plot(freq,ZL_a,'g-.','Linewidth',2); +ylabel('ZL (\Omega)'); +xlabel('freq (Hz)'); +xlim([freq(1) freq(end)]); +legend('\Re(Z_L)','\Im(Z_L)','Z_L analytic','Location','Best');