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diff --git a/openEMS/matlab/examples/antennas/Patch_Antenna.m b/openEMS/matlab/examples/antennas/Patch_Antenna.m
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+%
+% EXAMPLE / antennas / patch antenna
+%
+% This example demonstrates how to:
+%  - calculate the reflection coefficient of a patch antenna
+% 
+%
+% Tested with
+%  - Matlab 2009b
+%  - Octave 3.3.52
+%  - openEMS v0.0.23
+%
+% (C) 2010,2011 Thorsten Liebig <thorsten.liebig@uni-due.de>
+
+close all
+clear
+clc
+
+%% switches & options...
+postprocessing_only = 0;
+draw_3d_pattern = 0; % this may take a while...
+use_pml = 0;         % use pml boundaries instead of mur
+openEMS_opts = '';
+
+%% setup the simulation
+physical_constants;
+unit = 1e-3; % all length in mm
+
+% width in x-direction
+% length in y-direction
+% main radiation in z-direction
+patch.width  = 32.86; % resonant length
+patch.length = 41.37;
+
+substrate.epsR   = 3.38;
+substrate.kappa  = 1e-3 * 2*pi*2.45e9 * EPS0*substrate.epsR;
+substrate.width  = 60;
+substrate.length = 60;
+substrate.thickness = 1.524;
+substrate.cells = 4;
+
+feed.pos = -5.5;
+feed.width = 2;
+feed.R = 50; % feed resistance
+
+% size of the simulation box
+SimBox = [100 100 25];
+
+%% prepare simulation folder
+Sim_Path = 'tmp';
+Sim_CSX = 'patch_ant.xml';
+if (postprocessing_only==0)
+    [status, message, messageid] = rmdir( Sim_Path, 's' ); % clear previous directory
+    [status, message, messageid] = mkdir( Sim_Path ); % create empty simulation folder
+end
+
+%% setup FDTD parameter & excitation function
+max_timesteps = 30000;
+min_decrement = 1e-5; % equivalent to -50 dB
+f0 = 0e9; % center frequency
+fc = 3e9; % 20 dB corner frequency (in this case 0 Hz - 3e9 Hz)
+FDTD = InitFDTD( 'NrTS', max_timesteps, 'EndCriteria', min_decrement );
+FDTD = SetGaussExcite( FDTD, f0, fc );
+BC = {'MUR' 'MUR' 'MUR' 'MUR' 'MUR' 'MUR'}; % boundary conditions
+if (use_pml>0)
+    BC = {'PML_8' 'PML_8' 'PML_8' 'PML_8' 'PML_8' 'PML_8'}; % use pml instead of mur
+end
+FDTD = SetBoundaryCond( FDTD, BC );
+
+%% setup CSXCAD geometry & mesh
+% currently, openEMS cannot automatically generate a mesh
+max_res = c0 / (f0+fc) / unit / 20; % cell size: lambda/20
+CSX = InitCSX();
+mesh.x = [-SimBox(1)/2 SimBox(1)/2 -substrate.width/2 substrate.width/2 feed.pos];
+% add patch mesh with 2/3 - 1/3 rule
+mesh.x = [mesh.x -patch.width/2-max_res/2*0.66 -patch.width/2+max_res/2*0.33 patch.width/2+max_res/2*0.66 patch.width/2-max_res/2*0.33];
+mesh.x = SmoothMeshLines( mesh.x, max_res, 1.4); % create a smooth mesh between specified mesh lines
+mesh.y = [-SimBox(2)/2 SimBox(2)/2 -substrate.length/2 substrate.length/2 -feed.width/2 feed.width/2];
+% add patch mesh with 2/3 - 1/3 rule
+mesh.y = [mesh.y -patch.length/2-max_res/2*0.66 -patch.length/2+max_res/2*0.33 patch.length/2+max_res/2*0.66 patch.length/2-max_res/2*0.33];
+mesh.y = SmoothMeshLines( mesh.y, max_res, 1.4 );
+mesh.z = [-SimBox(3)/2 linspace(0,substrate.thickness,substrate.cells) SimBox(3) ];
+mesh.z = SmoothMeshLines( mesh.z, max_res, 1.4 );
+mesh = AddPML( mesh, [8 8 8 8 8 8] ); % add equidistant cells (air around the structure)
+CSX = DefineRectGrid( CSX, unit, mesh );
+
+%% create patch
+CSX = AddMetal( CSX, 'patch' ); % create a perfect electric conductor (PEC)
+start = [-patch.width/2 -patch.length/2 substrate.thickness];
+stop  = [ patch.width/2  patch.length/2 substrate.thickness];
+CSX = AddBox(CSX,'patch',10,start,stop);
+
+%% create substrate
+CSX = AddMaterial( CSX, 'substrate' );
+CSX = SetMaterialProperty( CSX, 'substrate', 'Epsilon', substrate.epsR, 'Kappa', substrate.kappa );
+start = [-substrate.width/2 -substrate.length/2 0];
+stop  = [ substrate.width/2  substrate.length/2 substrate.thickness];
+CSX = AddBox( CSX, 'substrate', 0, start, stop );
+
+%% create ground (same size as substrate)
+CSX = AddMetal( CSX, 'gnd' ); % create a perfect electric conductor (PEC)
+start(3)=0;
+stop(3) =0;
+CSX = AddBox(CSX,'gnd',10,start,stop);
+
+%% apply the excitation & resist as a current source
+start = [feed.pos-.1 -feed.width/2 0];
+stop  = [feed.pos+.1 +feed.width/2 substrate.thickness];
+[CSX] = AddLumpedPort(CSX, 5 ,1 ,feed.R, start, stop, [0 0 1], true);
+
+%% dump magnetic field over the patch antenna
+CSX = AddDump( CSX, 'Ht_', 'DumpType', 1, 'DumpMode', 2); % cell interpolated
+start = [-patch.width -patch.length substrate.thickness+1];
+stop  = [ patch.width  patch.length substrate.thickness+1];
+CSX = AddBox( CSX, 'Ht_', 0, start, stop );
+
+%%nf2ff calc
+[CSX nf2ff] = CreateNF2FFBox(CSX, 'nf2ff', -SimBox/2, SimBox/2);
+
+if (postprocessing_only==0)
+    %% 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, openEMS_opts );
+end
+
+%% postprocessing & do the plots
+freq = linspace( max([1e9,f0-fc]), f0+fc, 501 );
+U = ReadUI( {'port_ut1','et'}, 'tmp/', freq ); % time domain/freq domain voltage
+I = ReadUI( 'port_it1', 'tmp/', freq ); % time domain/freq domain current (half time step is corrected)
+
+% plot time domain voltage
+figure
+[ax,h1,h2] = plotyy( U.TD{1}.t/1e-9, U.TD{1}.val, U.TD{2}.t/1e-9, U.TD{2}.val );
+set( h1, 'Linewidth', 2 );
+set( h1, 'Color', [1 0 0] );
+set( h2, 'Linewidth', 2 );
+set( h2, 'Color', [0 0 0] );
+grid on
+title( 'time domain voltage' );
+xlabel( 'time t / ns' );
+ylabel( ax(1), 'voltage ut1 / V' );
+ylabel( ax(2), 'voltage et / V' );
+% now make the y-axis symmetric to y=0 (align zeros of y1 and y2)
+y1 = ylim(ax(1));
+y2 = ylim(ax(2));
+ylim( ax(1), [-max(abs(y1)) max(abs(y1))] );
+ylim( ax(2), [-max(abs(y2)) max(abs(y2))] );
+
+% plot feed point impedance
+figure
+Zin = U.FD{1}.val ./ I.FD{1}.val;
+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
+uf_inc = 0.5*(U.FD{1}.val + I.FD{1}.val * 50);
+if_inc = 0.5*(I.FD{1}.val - U.FD{1}.val / 50);
+uf_ref = U.FD{1}.val - uf_inc;
+if_ref = I.FD{1}.val - if_inc;
+s11 = uf_ref ./ uf_inc;
+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}|' );
+
+P_in = 0.5*U.FD{1}.val .* conj( I.FD{1}.val );
+
+%% NFFF contour plots %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+f_res_ind = find(s11==min(s11));
+f_res = freq(f_res_ind);
+
+% calculate the far field at phi=0 degrees and at phi=90 degrees
+thetaRange = (0:2:359) - 180;
+phiRange = [0 90];
+disp( 'calculating far field at phi=[0 90] deg...' );
+nf2ff = CalcNF2FF(nf2ff, Sim_Path, f_res, thetaRange*pi/180, phiRange*pi/180);
+
+Dlog=10*log10(nf2ff.Dmax);
+
+% display power and directivity
+disp( ['radiated power: Prad = ' num2str(nf2ff.Prad) ' Watt']);
+disp( ['directivity: Dmax = ' num2str(Dlog) ' dBi'] );
+disp( ['efficiency: nu_rad = ' num2str(100*nf2ff.Prad./real(P_in(f_res_ind))) ' %']);
+
+% display phi
+figure
+plotFFdB(nf2ff,'xaxis','theta','param',[1 2]);
+drawnow
+
+if (draw_3d_pattern==0)
+    return
+end
+
+%% calculate 3D pattern
+phiRange = 0:2:360;
+thetaRange = 0:2:180;
+disp( 'calculating 3D far field...' );
+nf2ff = CalcNF2FF(nf2ff, Sim_Path, f_res, thetaRange*pi/180, phiRange*pi/180, 'Verbose',2,'Outfile','nf2ff_3D.h5');
+figure
+plotFF3D(nf2ff);
+
+
+%% visualize magnetic fields
+% you will find vtk dump files in the simulation folder (tmp/)
+% use paraview to visulaize them