Imported Upstream version 0.0.34

1 files changed, 197 insertions, 0 deletions

diff --git a/openEMS/matlab/Tutorials/Bent_Patch_Antenna.m b/openEMS/matlab/Tutorials/Bent_Patch_Antenna.m
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+%
+% Tutorials / bent patch antenna
+%
+% Describtion at:
+% http://openems.de/index.php/Tutorial:_Bent_Patch_Antenna
+%
+% Tested with
+%  - Matlab 2011a / Octave 4.0
+%  - openEMS v0.0.33
+%
+% (C) 2013-2015 Thorsten Liebig <thorsten.liebig@uni-due.de>
+
+close all
+clear
+clc
+
+%% setup the simulation
+physical_constants;
+unit = 1e-3; % all length in mm
+
+% patch width in alpha-direction
+patch.width  = 32; % resonant length in alpha-direction
+patch.radius = 50; % radius
+patch.length = 40; % patch length in z-direction
+
+%substrate setup
+substrate.epsR   = 3.38;
+substrate.kappa  = 1e-3 * 2*pi*2.45e9 * EPS0*substrate.epsR;
+substrate.width  = 80;
+substrate.length = 90;
+substrate.thickness = 1.524;
+substrate.cells = 4;
+
+%setup feeding
+feed.pos = -5.5;   %feeding position in x-direction
+feed.width = 2;  %feeding port width
+feed.R = 50;     %feed resistance
+
+% size of the simulation box
+SimBox.rad    = 2*100;
+SimBox.height = 1.5*200;
+
+%% setup FDTD parameter & excitation function
+FDTD = InitFDTD('CoordSystem', 1); % init a cylindrical FDTD
+f0 = 2e9; % center frequency
+fc = 1e9; % 20 dB corner frequency
+FDTD = SetGaussExcite( FDTD, f0, fc );
+BC = {'MUR' 'MUR' 'MUR' 'MUR' 'MUR' 'MUR'}; % boundary conditions
+FDTD = SetBoundaryCond( FDTD, BC );
+
+%% setup CSXCAD geometry & mesh
+% init a cylindrical mesh
+CSX = InitCSX('CoordSystem',1);
+
+% calculate some width as an angle in radiant
+patch_ang_width = patch.width/(patch.radius+substrate.thickness);
+substr_ang_width = substrate.width/patch.radius;
+feed_angle = feed.pos/patch.radius;
+
+%% create patch
+CSX = AddMetal( CSX, 'patch' ); % create a perfect electric conductor (PEC)
+start = [patch.radius+substrate.thickness -patch_ang_width/2 -patch.length/2 ];
+stop  = [patch.radius+substrate.thickness  patch_ang_width/2  patch.length/2 ];
+CSX = AddBox(CSX,'patch',10,start,stop); % add a box-primitive to the metal property 'patch'
+
+%% create substrate
+CSX = AddMaterial( CSX, 'substrate' );
+CSX = SetMaterialProperty( CSX, 'substrate', 'Epsilon', substrate.epsR, 'Kappa', substrate.kappa );
+start = [patch.radius                     -substr_ang_width/2 -substrate.length/2];
+stop  = [patch.radius+substrate.thickness  substr_ang_width/2  substrate.length/2];
+CSX = AddBox( CSX, 'substrate', 0, start, stop);
+
+%% save current density oon the patch
+CSX = AddDump(CSX, 'Jt_patch','DumpType',3,'FileType',1);
+start = [patch.radius+substrate.thickness -substr_ang_width/2 -substrate.length/2];
+stop  = [patch.radius+substrate.thickness +substr_ang_width/2  substrate.length/2];
+CSX = AddBox( CSX, 'Jt_patch', 0, start, stop );
+
+%% create ground (not really necessary, only for esthetic reasons)
+CSX = AddMetal( CSX, 'gnd' ); % create a perfect electric conductor (PEC)
+start = [patch.radius -substr_ang_width/2 -substrate.length/2];
+stop  = [patch.radius +substr_ang_width/2 +substrate.length/2];
+CSX = AddBox(CSX,'gnd',10,start,stop);
+
+%% apply the excitation & resist as a current source
+start = [patch.radius                      feed_angle 0];
+stop  = [patch.radius+substrate.thickness  feed_angle 0];
+[CSX port] = AddLumpedPort(CSX, 50 ,1 ,feed.R, start, stop, [1 0 0], true);
+
+
+%% finalize the mesh
+% detect all edges
+mesh = DetectEdges(CSX);
+
+% add the simulation domain size
+mesh.r = [mesh.r patch.radius+[-20 SimBox.rad]];
+mesh.a = [mesh.a -0.75*pi 0.75*pi];
+mesh.z = [mesh.z -SimBox.height/2 SimBox.height/2];
+
+% add some lines for the substrate
+mesh.r = [mesh.r patch.radius+linspace(0,substrate.thickness,substrate.cells)];
+
+% generate a smooth mesh with max. cell size: lambda_min / 20
+max_res = c0 / (f0+fc) / unit / 20;
+max_ang = max_res/(SimBox.rad+patch.radius); % max res in radiant
+mesh = SmoothMesh(mesh, [max_res max_ang max_res], 1.4);
+
+disp(['Num of cells: ' num2str(numel(mesh.r)*numel(mesh.a)*numel(mesh.z))]);
+CSX = DefineRectGrid( CSX, unit, mesh );
+
+%% create nf2ff, keep some distance to the boundary conditions, e.g. 8 cells pml
+start = [mesh.r(4)     mesh.a(8)     mesh.z(8)];
+stop  = [mesh.r(end-9) mesh.a(end-9) mesh.z(end-9)];
+[CSX nf2ff] = CreateNF2FFBox(CSX, 'nf2ff', start, stop, 'Directions',[1 1 1 1 1 1]);
+
+%% prepare simulation folder & run
+Sim_Path = ['tmp_' mfilename];
+Sim_CSX  = [mfilename '.xml'];
+
+[status, message, messageid] = rmdir( Sim_Path, 's' ); % clear previous directory
+[status, message, messageid] = mkdir( Sim_Path ); % create empty simulation folder
+
+% write openEMS compatible xml-file
+WriteOpenEMS( [Sim_Path '/' Sim_CSX], FDTD, CSX );
+
+% show the structure
+CSXGeomPlot( [Sim_Path '/' Sim_CSX] );
+
+% run openEMS
+RunOpenEMS( Sim_Path, Sim_CSX);
+
+%% postprocessing & do the plots
+freq = linspace( max([1e9,f0-fc]), f0+fc, 501 );
+port = calcPort(port, Sim_Path, freq);
+
+Zin = port.uf.tot ./ port.if.tot;
+s11 = port.uf.ref ./ port.uf.inc;
+P_in = 0.5*real(port.uf.tot .* conj(port.if.tot)); % antenna feed power
+
+% plot feed point impedance
+figure
+plot( freq/1e6, real(Zin), 'k-', 'Linewidth', 2 );
+hold on
+grid on
+plot( freq/1e6, imag(Zin), 'r--', 'Linewidth', 2 );
+title( 'feed point impedance' );
+xlabel( 'frequency f / MHz' );
+ylabel( 'impedance Z_{in} / Ohm' );
+legend( 'real', 'imag' );
+
+% plot reflection coefficient S11
+figure
+plot( freq/1e6, 20*log10(abs(s11)), 'k-', 'Linewidth', 2 );
+grid on
+title( 'reflection coefficient S_{11}' );
+xlabel( 'frequency f / MHz' );
+ylabel( 'reflection coefficient |S_{11}|' );
+
+drawnow
+
+%find resonance frequncy from s11
+f_res_ind = find(s11==min(s11));
+f_res = freq(f_res_ind);
+
+%%
+disp('dumping resonant current distribution to vtk file, use Paraview to visualize');
+ConvertHDF5_VTK([Sim_Path '/Jt_patch.h5'],[Sim_Path '/Jf_patch'],'Frequency',f_res,'FieldName','J-Field');
+
+%% NFFF contour plots %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% calculate the far field at phi=0 degree
+nf2ff = CalcNF2FF(nf2ff, Sim_Path, f_res, [-180:2:180]*pi/180, 0,'Center',[patch.radius+substrate.thickness 0 0]*unit, 'Outfile','pattern_phi_0.h5');
+% normalized directivity as polar plot
+figure
+polarFF(nf2ff,'xaxis','theta','param',1,'normalize',1)
+
+% calculate the far field at phi=0 degree
+nf2ff = CalcNF2FF(nf2ff, Sim_Path, f_res, pi/2, (-180:2:180)*pi/180,'Center',[patch.radius+substrate.thickness 0 0]*unit, 'Outfile','pattern_theta_90.h5');
+% normalized directivity as polar plot
+figure
+polarFF(nf2ff,'xaxis','phi','param',1,'normalize',1)
+
+% display power and directivity
+disp( ['radiated power: Prad = ' num2str(nf2ff.Prad) ' Watt']);
+disp( ['directivity: Dmax = ' num2str(nf2ff.Dmax) ' (' num2str(10*log10(nf2ff.Dmax)) ' dBi)'] );
+disp( ['efficiency: nu_rad = ' num2str(100*nf2ff.Prad./real(P_in(f_res_ind))) ' %']);
+
+drawnow
+
+%%
+disp( 'calculating 3D far field pattern and dumping to vtk (use Paraview to visualize)...' );
+thetaRange = (0:2:180);
+phiRange = (0:2:360) - 180;
+nf2ff = CalcNF2FF(nf2ff, Sim_Path, f_res, thetaRange*pi/180, phiRange*pi/180,'Verbose',1,'Outfile','3D_Pattern.h5','Center',[patch.radius+substrate.thickness 0 0]*unit);
+
+figure
+plotFF3D(nf2ff,'logscale',-20);
+