153 lines
4.0 KiB
Matlab
153 lines
4.0 KiB
Matlab
function pass = Coax
|
|
|
|
physical_constants;
|
|
|
|
|
|
ENABLE_PLOTS = 1;
|
|
CLEANUP = 0; % if enabled and result is PASS, remove simulation folder
|
|
STOP_IF_FAILED = 1; % if enabled and result is FAILED, stop with error
|
|
|
|
% LIMITS
|
|
upper_error = 0.036; % max +3.6%
|
|
lower_error = 0; % max -0.0%
|
|
|
|
% structure
|
|
abs_length = 250;
|
|
length = 1000;
|
|
coax_rad_i = 100;
|
|
coax_rad_ai = 230;
|
|
coax_rad_aa = 240;
|
|
mesh_res = [5 5 5];
|
|
f_start = 0;
|
|
f_stop = 1e9;
|
|
|
|
Sim_Path = 'tmp';
|
|
Sim_CSX = 'coax.xml';
|
|
|
|
[status,message,messageid]=mkdir(Sim_Path);
|
|
|
|
%setup FDTD parameter
|
|
FDTD = InitFDTD(5e5,1e-6);
|
|
FDTD = SetGaussExcite(FDTD,(f_stop-f_start)/2,(f_stop-f_start)/2);
|
|
BC = [1 1 1 1 1 1] * 0;
|
|
FDTD = SetBoundaryCond(FDTD,BC);
|
|
|
|
%setup CSXCAD geometry
|
|
CSX = InitCSX();
|
|
mesh.x = -2.5*mesh_res(1)-coax_rad_aa : mesh_res(1) : coax_rad_aa+2.5*mesh_res(1);
|
|
mesh.y = mesh.x;
|
|
mesh.z = 0 : mesh_res(3) : length;
|
|
CSX = DefineRectGrid(CSX, 1e-3,mesh);
|
|
|
|
%create copper
|
|
CSX = AddMetal(CSX,'PEC');
|
|
|
|
%%%fake pml
|
|
finalKappa = 0.3/abs_length^4;
|
|
finalSigma = finalKappa*MUE0/EPS0;
|
|
CSX = AddMaterial(CSX,'pml');
|
|
CSX = SetMaterialProperty(CSX,'pml','Kappa',finalKappa);
|
|
CSX = SetMaterialProperty(CSX,'pml','Sigma',finalSigma);
|
|
CSX = SetMaterialWeight(CSX,'pml','Kappa',['pow(abs(z)-' num2str(length-abs_length) ',4)']);
|
|
CSX = SetMaterialWeight(CSX,'pml','Sigma',['pow(abs(z)-' num2str(length-abs_length) ',4)']);
|
|
|
|
%%% coax
|
|
start = [0, 0 , 0];stop = [0, 0 , length];
|
|
CSX = AddCylinder(CSX,'PEC',0 ,start,stop,coax_rad_i); % inner conductor
|
|
CSX = AddCylindricalShell(CSX,'PEC',0 ,start,stop,0.5*(coax_rad_aa+coax_rad_ai),(coax_rad_aa-coax_rad_ai)); % outer conductor
|
|
|
|
%%% add PML
|
|
start(3) = length-abs_length;
|
|
CSX = AddCylindricalShell(CSX,'pml',0 ,start,stop,0.5*(coax_rad_i+coax_rad_ai),(coax_rad_ai-coax_rad_i));
|
|
start(3) = 0; stop(3)=mesh_res(1)/2;
|
|
CSX = AddExcitation(CSX,'excite',0,[1 1 0]);
|
|
weight{1} = '(x)/(x*x+y*y)';
|
|
weight{2} = 'y/pow(rho,2)';
|
|
weight{3} = 0;
|
|
CSX = SetExcitationWeight(CSX, 'excite', weight );
|
|
CSX = AddCylindricalShell(CSX,'excite',0 ,start,stop,0.5*(coax_rad_i+coax_rad_ai),(coax_rad_ai-coax_rad_i));
|
|
|
|
%dump
|
|
CSX = AddDump(CSX,'Et_',0,2);
|
|
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_',1,2);
|
|
CSX = AddBox(CSX,'Ht_',0,start,stop);
|
|
|
|
%voltage calc
|
|
CSX = AddProbe(CSX,'ut1',0);
|
|
start = [ coax_rad_i 0 length/2 ];stop = [ coax_rad_ai 0 length/2 ];
|
|
CSX = AddBox(CSX,'ut1', 0 ,start,stop);
|
|
|
|
%current calc
|
|
CSX = AddProbe(CSX,'it1',1);
|
|
mid = 0.5*(coax_rad_i+coax_rad_ai);
|
|
start = [ -mid -mid length/2 ];stop = [ mid mid length/2 ];
|
|
CSX = AddBox(CSX,'it1', 0 ,start,stop);
|
|
|
|
%Write openEMS compatible xml-file
|
|
WriteOpenEMS([Sim_Path '/' Sim_CSX],FDTD,CSX);
|
|
|
|
%cd to working dir and run openEMS
|
|
savePath = pwd();
|
|
cd(Sim_Path); %cd to working dir
|
|
invoke_openEMS( Sim_CSX );
|
|
UI = ReadUI( {'ut1','it1'} );
|
|
cd(savePath);
|
|
|
|
|
|
|
|
%
|
|
% analysis
|
|
%
|
|
|
|
f = UI.FD{2}.f;
|
|
u = UI.FD{1}.val;
|
|
i = UI.FD{2}.val;
|
|
|
|
f_idx_start = interp1( f, 1:numel(f), f_start, 'nearest' );
|
|
f_idx_stop = interp1( f, 1:numel(f), f_stop, 'nearest' );
|
|
f = f(f_idx_start:f_idx_stop);
|
|
u = u(f_idx_start:f_idx_stop);
|
|
i = i(f_idx_start:f_idx_stop);
|
|
|
|
Z = abs(u./i);
|
|
|
|
% analytic formular for characteristic impedance
|
|
Z0 = sqrt(MUE0/EPS0) * log(coax_rad_ai/coax_rad_i) / (2*pi);
|
|
upper_limit = Z0 * (1+upper_error);
|
|
lower_limit = Z0 * (1-lower_error);
|
|
|
|
if ENABLE_PLOTS
|
|
upper = upper_limit * ones(1,size(Z,2));
|
|
lower = lower_limit * ones(1,size(Z,2));
|
|
Z0_plot = Z0 * ones(1,size(Z,2));
|
|
figure
|
|
plot(f/1e9,[Z;upper;lower])
|
|
hold on
|
|
plot(f/1e9,Z0_plot,'m-.','LineWidth',2)
|
|
hold off
|
|
xlabel('Frequency (GHz)')
|
|
ylabel('Impedance (Ohm)')
|
|
legend( {'sim', 'upper limit', 'lower limit', 'theoretical'} );
|
|
end
|
|
|
|
pass = check_limits( Z, upper_limit, lower_limit );
|
|
if pass
|
|
disp( 'combinedtests/Coax.m (characteristic impedance): pass' );
|
|
else
|
|
disp( 'combinedtests/Coax.m (characteristic impedance): * FAILED *' );
|
|
end
|
|
|
|
|
|
|
|
|
|
if pass && CLEANUP
|
|
rmdir( [Sim_Path '/' Sim_CSX], 's' );
|
|
end
|
|
if ~pass && STOP_IF_FAILED
|
|
error 'test failed';
|
|
end
|