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matlab examples: update to patch-antenna and new patch antenna array example

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Thorsten Liebig 2010-12-28 13:36:19 +01:00
parent 14aa47b3c5
commit 5a9b6e1bd5
2 changed files with 364 additions and 66 deletions
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119
matlab/examples/antennas/Patch_Antenna.m
View File

@ -8,7 +8,7 @@
% Tested with % Tested with
% - Matlab 2009b % - Matlab 2009b
% - Octave 3.3.52 % - Octave 3.3.52
% - openEMS v0.0.14 % - openEMS v0.0.17
% %
% (C) 2010 Thorsten Liebig <thorsten.liebig@uni-due.de> % (C) 2010 Thorsten Liebig <thorsten.liebig@uni-due.de>
@ -16,6 +16,12 @@ close all
clear clear
clc clc
%% switches & options...
postprocessing_only = 0;
draw_3d_pattern = 1; % this may take a while...
use_pml = 0; % use pml boundaries instead of mur
openEMS_opts = '';
%% setup the simulation %% setup the simulation
physical_constants; physical_constants;
unit = 1e-3; % all length in mm unit = 1e-3; % all length in mm
@ -27,40 +33,45 @@ patch.width = 32.86; % resonant length
patch.length = 41.37; patch.length = 41.37;
substrate.epsR = 3.38; substrate.epsR = 3.38;
substrate.width = 120; substrate.kappa = 1e-3 * 2*pi*2.45e9 * EPS0*substrate.epsR;
substrate.length = 120; substrate.width = 60;
substrate.length = 60;
substrate.thickness = 1.524; substrate.thickness = 1.524;
substrate.cells = 5; substrate.cells = 4;
feed.pos = -4.5; feed.pos = -5.5;
feed.width = 0.5; feed.width = 2;
feed.R = 50; % feed resistance feed.R = 50; % feed resistance
% size of the simulation box % size of the simulation box
SimBox = [200 200 50]; SimBox = [100 100 25];
%% prepare simulation folder %% prepare simulation folder
Sim_Path = 'tmp'; Sim_Path = 'tmp';
Sim_CSX = 'patch_ant.xml'; Sim_CSX = 'patch_ant.xml';
if (postprocessing_only==0)
[status, message, messageid] = rmdir( Sim_Path, 's' ); % clear previous directory [status, message, messageid] = rmdir( Sim_Path, 's' ); % clear previous directory
[status, message, messageid] = mkdir( Sim_Path ); % create empty simulation folder [status, message, messageid] = mkdir( Sim_Path ); % create empty simulation folder
end
%% setup FDTD parameter & excitation function %% setup FDTD parameter & excitation function
max_timesteps = 30000; max_timesteps = 30000;
min_decrement = 1e-5; % equivalent to -50 dB min_decrement = 1e-5; % equivalent to -50 dB
f0 = 2e9; % center frequency f0 = 0e9; % center frequency
fc = 1e9; % 10 dB corner frequency (in this case 1e9 Hz - 3e9 Hz) fc = 3e9; % 10 dB corner frequency (in this case 0 Hz - 3e9 Hz)
FDTD = InitFDTD( max_timesteps, min_decrement ); FDTD = InitFDTD( max_timesteps, min_decrement );
FDTD = SetGaussExcite( FDTD, f0, fc ); FDTD = SetGaussExcite( FDTD, f0, fc );
BC = {'MUR' 'MUR' 'MUR' 'MUR' 'PEC' 'MUR'}; % boundary conditions BC = {'MUR' 'MUR' 'MUR' 'MUR' 'MUR' 'MUR'}; % boundary conditions
% BC = {'PML_8' 'PML_8' 'PML_8' 'PML_8' 'PEC' 'PML_8'}; % use pml instead of mur 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 ); FDTD = SetBoundaryCond( FDTD, BC );
%% setup CSXCAD geometry & mesh %% setup CSXCAD geometry & mesh
% currently, openEMS cannot automatically generate a mesh % currently, openEMS cannot automatically generate a mesh
max_res = c0 / (f0+fc) / unit / 20; % cell size: lambda/20 max_res = c0 / (f0+fc) / unit / 20; % cell size: lambda/20
CSX = InitCSX(); CSX = InitCSX();
mesh.x = [-SimBox(1)/2 SimBox(1)/2 -substrate.width/2 substrate.width/2 feed.pos-feed.width/2 feed.pos+feed.width/2]; 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 % 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 = [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.x = SmoothMeshLines( mesh.x, max_res, 1.4); % create a smooth mesh between specified mesh lines
@ -81,7 +92,7 @@ CSX = AddBox(CSX,'patch',10,start,stop);
%% create substrate %% create substrate
CSX = AddMaterial( CSX, 'substrate' ); CSX = AddMaterial( CSX, 'substrate' );
CSX = SetMaterialProperty( CSX, 'substrate', 'Epsilon', substrate.epsR ); CSX = SetMaterialProperty( CSX, 'substrate', 'Epsilon', substrate.epsR, 'Kappa', substrate.kappa );
start = [-substrate.width/2 -substrate.length/2 0]; start = [-substrate.width/2 -substrate.length/2 0];
stop = [ substrate.width/2 substrate.length/2 substrate.thickness]; stop = [ substrate.width/2 substrate.length/2 substrate.thickness];
CSX = AddBox( CSX, 'substrate', 0, start, stop ); CSX = AddBox( CSX, 'substrate', 0, start, stop );
@ -93,28 +104,9 @@ stop(3) =0;
CSX = AddBox(CSX,'gnd',10,start,stop); CSX = AddBox(CSX,'gnd',10,start,stop);
%% apply the excitation & resist as a current source %% apply the excitation & resist as a current source
% this creates a "port" start = [feed.pos -feed.width/2 0];
CSX = AddMaterial( CSX, 'resist' ); stop = [feed.pos +feed.width/2 substrate.thickness];
kappa = substrate.thickness/feed.R/feed.width^2/unit; [CSX port] = AddLumpedPort(CSX,1,feed.R, start, stop,[0 0 1],'excite');
CSX = SetMaterialProperty( CSX, 'resist', 'Kappa', kappa );
start = [feed.pos-feed.width/2 -feed.width/2 0];
stop = [feed.pos+feed.width/2 feed.width/2 substrate.thickness];
CSX = AddBox( CSX, 'resist', 15, start, stop );
CSX = AddExcitation( CSX, 'excite', 0, [0 0 1] ); % excitation in z-direction
CSX = AddBox( CSX, 'excite', 0, start, stop );
%% define voltage calc boxes
CSX = AddProbe( CSX, 'ut1', 0 );
start = [feed.pos 0 0];
stop = [feed.pos 0 substrate.thickness];
CSX = AddBox( CSX, 'ut1', 0 , stop, start );
%% define current calc boxes
CSX = AddProbe( CSX, 'it1', 1 );
start = [feed.pos-feed.width -feed.width substrate.thickness/2];
stop = [feed.pos+feed.width feed.width substrate.thickness/2];
CSX = AddBox( CSX, 'it1', 0, start, stop );
%% dump magnetic field over the patch antenna %% dump magnetic field over the patch antenna
CSX = AddDump( CSX, 'Ht_', 'DumpType', 1, 'DumpMode', 2); % cell interpolated CSX = AddDump( CSX, 'Ht_', 'DumpType', 1, 'DumpMode', 2); % cell interpolated
@ -125,6 +117,7 @@ CSX = AddBox( CSX, 'Ht_', 0, start, stop );
%%nf2ff calc %%nf2ff calc
[CSX nf2ff] = CreateNF2FFBox(CSX, 'nf2ff', -SimBox/2, SimBox/2); [CSX nf2ff] = CreateNF2FFBox(CSX, 'nf2ff', -SimBox/2, SimBox/2);
if (postprocessing_only==0)
%% write openEMS compatible xml-file %% write openEMS compatible xml-file
WriteOpenEMS( [Sim_Path '/' Sim_CSX], FDTD, CSX ); WriteOpenEMS( [Sim_Path '/' Sim_CSX], FDTD, CSX );
@ -132,14 +125,13 @@ WriteOpenEMS( [Sim_Path '/' Sim_CSX], FDTD, CSX );
CSXGeomPlot( [Sim_Path '/' Sim_CSX] ); CSXGeomPlot( [Sim_Path '/' Sim_CSX] );
%% run openEMS %% run openEMS
openEMS_opts = '';
openEMS_opts = [openEMS_opts ' --engine=fastest'];
RunOpenEMS( Sim_Path, Sim_CSX, openEMS_opts ); RunOpenEMS( Sim_Path, Sim_CSX, openEMS_opts );
end
%% postprocessing & do the plots %% postprocessing & do the plots
freq = linspace( f0-fc, f0+fc, 501 ); freq = linspace( max([1e9,f0-fc]), f0+fc, 501 );
U = ReadUI( {'ut1','et'}, 'tmp/', freq ); % time domain/freq domain voltage U = ReadUI( {'port_ut1','et'}, 'tmp/', freq ); % time domain/freq domain voltage
I = ReadUI( 'it1', 'tmp/', freq ); % time domain/freq domain current (half time step is corrected) I = ReadUI( 'port_it1', 'tmp/', freq ); % time domain/freq domain current (half time step is corrected)
% plot time domain voltage % plot time domain voltage
figure figure
@ -184,19 +176,24 @@ title( 'reflection coefficient S_{11}' );
xlabel( 'frequency f / MHz' ); xlabel( 'frequency f / MHz' );
ylabel( 'reflection coefficient |S_{11}|' ); ylabel( 'reflection coefficient |S_{11}|' );
P_in = 0.5*U.FD{1}.val .* conj( I.FD{1}.val );
%% NFFF contour plots %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% NFFF contour plots %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
f0 = freq(find(s11==min(s11))); 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 % calculate the far field at phi=0 degrees and at phi=90 degrees
thetaRange = 0:2:359; thetaRange = (0:2:359) - 180;
r = 1; % evaluate fields at radius r r = 1; % evaluate fields at radius r
disp( 'calculating far field at phi=[0 90] deg...' ); disp( 'calculating far field at phi=[0 90] deg...' );
[E_far_theta,E_far_phi,Prad,Dmax] = AnalyzeNF2FF( Sim_Path, nf2ff, f0, thetaRange, [0 90], r ); [E_far_theta,E_far_phi,Prad,Dmax] = AnalyzeNF2FF( Sim_Path, nf2ff, f_res, thetaRange, [0 90], r );
Dlog=10*log10(Dmax);
% display power and directivity % display power and directivity
disp( ['radiated power: Prad = ' num2str(Prad)] ); disp( ['radiated power: Prad = ' num2str(Prad) ' Watt']);
disp( ['directivity: Dmax = ' num2str(Dmax)] ); disp( ['directivity: Dmax = ' num2str(Dlog) ' dBi'] );
disp( ['efficiency: nu_rad = ' num2str(100*Prad./real(P_in(f_res_ind))) ' %']);
% calculate the e-field magnitude for phi = 0 deg % calculate the e-field magnitude for phi = 0 deg
E_phi0_far = zeros(1,numel(thetaRange)); E_phi0_far = zeros(1,numel(thetaRange));
@ -204,12 +201,16 @@ for n=1:numel(thetaRange)
E_phi0_far(n) = norm( [E_far_theta(n,1) E_far_phi(n,1)] ); E_phi0_far(n) = norm( [E_far_theta(n,1) E_far_phi(n,1)] );
end end
E_phi0_far_log = 20*log10(abs(E_phi0_far)/max(abs(E_phi0_far)));
E_phi0_far_log = E_phi0_far_log + Dlog;
% display polar plot % display polar plot
figure figure
polar( thetaRange/180*pi, E_phi0_far ); plot( thetaRange, E_phi0_far_log ,'k-' );
ylabel( 'theta / deg' ); xlabel( 'theta (deg)' );
title( ['electrical far field (V/m) @r=' num2str(r) ' m phi=0 deg'] ); ylabel( 'directivity (dBi)');
legend( 'e-field magnitude', 'Location', 'BestOutside' ); grid on;
hold on;
% calculate the e-field magnitude for phi = 90 deg % calculate the e-field magnitude for phi = 90 deg
E_phi90_far = zeros(1,numel(thetaRange)); E_phi90_far = zeros(1,numel(thetaRange));
@ -217,21 +218,25 @@ for n=1:numel(thetaRange)
E_phi90_far(n) = norm([E_far_theta(n,2) E_far_phi(n,2)]); E_phi90_far(n) = norm([E_far_theta(n,2) E_far_phi(n,2)]);
end end
% display polar plot E_phi90_far_log = 20*log10(abs(E_phi90_far)/max(abs(E_phi90_far)));
figure E_phi90_far_log = E_phi90_far_log + Dlog;
polar( thetaRange/180*pi, E_phi90_far );
ylabel( 'theta / deg' );
title( ['electrical far field (V/m) @r=' num2str(r) ' m phi=90 deg'] );
legend( 'e-field magnitude', 'Location', 'BestOutside' );
% display polar plot
plot( thetaRange, E_phi90_far_log ,'r-' );
legend('phi=0','phi=90')
if (draw_3d_pattern==0)
return
end
%% calculate 3D pattern %% calculate 3D pattern
phiRange = 0:15:360; phiRange = 0:15:360;
thetaRange = 0:10:180; thetaRange = 0:10:180;
r = 1; % evaluate fields at radius r r = 1; % evaluate fields at radius r
disp( 'calculating 3D far field...' ); disp( 'calculating 3D far field...' );
[E_far_theta,E_far_phi] = AnalyzeNF2FF( Sim_Path, nf2ff, f0, thetaRange, phiRange, r ); [E_far_theta,E_far_phi] = AnalyzeNF2FF( Sim_Path, nf2ff, f_res, thetaRange, phiRange, r );
E_far = sqrt( abs(E_far_theta).^2 + abs(E_far_phi).^2 ); E_far = sqrt( abs(E_far_theta).^2 + abs(E_far_phi).^2 );
E_far_normalized = E_far / max(E_far(:)); E_far_normalized = E_far / max(E_far(:)) * Dmax;
[theta,phi] = ndgrid(thetaRange/180*pi,phiRange/180*pi); [theta,phi] = ndgrid(thetaRange/180*pi,phiRange/180*pi);
x = E_far_normalized .* sin(theta) .* cos(phi); x = E_far_normalized .* sin(theta) .* cos(phi);
y = E_far_normalized .* sin(theta) .* sin(phi); y = E_far_normalized .* sin(theta) .* sin(phi);

293
matlab/examples/antennas/Patch_Antenna_Array.m Normal file
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@ -0,0 +1,293 @@
%
% EXAMPLE / antennas / patch antenna array
%
% This example demonstrates how to:
% - calculate the reflection coefficient of a patch antenna array
%
%
% Tested with
% - Matlab 2009b
% - Octave 3.3.52
% - openEMS v0.0.17
%
% (C) 2010 Thorsten Liebig <thorsten.liebig@uni-due.de>
close all
clear
clc
%% switches & options...
postprocessing_only = 0;
draw_3d_pattern = 1; % this may take a (very long) 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;
% define array size and dimensions
array.xn = 4;
array.yn = 4;
array.x_spacing = patch.width * 3;
array.y_spacing = patch.length * 3;
substrate.epsR = 3.38;
substrate.kappa = 1e-3 * 2*pi*2.45e9 * EPS0*substrate.epsR;
substrate.width = 60 + (array.xn-1) * array.x_spacing;
substrate.length = 60 + (array.yn-1) * array.y_spacing;
substrate.thickness = 1.524;
substrate.cells = 4;
feed.pos = -5.5;
feed.width = 2;
feed.R = 50; % feed resistance
% size of the simulation box around the array
SimBox = [50+substrate.width 50+substrate.length 25];
%% prepare simulation folder
Sim_Path = 'tmp';
Sim_CSX = 'patch_array.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; % 10 dB corner frequency (in this case 0 Hz - 3e9 Hz)
FDTD = InitFDTD( max_timesteps, 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];
mesh.y = [-SimBox(2)/2 SimBox(2)/2 -substrate.length/2 substrate.length/2];
mesh.z = [-SimBox(3)/2 linspace(0,substrate.thickness,substrate.cells) SimBox(3) ];
mesh.z = SmoothMeshLines( mesh.z, max_res, 1.4 );
for xn=1:array.xn
for yn=1:array.yn
midX = (array.xn/2 - xn + 1/2) * array.x_spacing;
midY = (array.yn/2 - yn + 1/2) * array.y_spacing;
% feeding mesh
mesh.x = [mesh.x midX+feed.pos];
mesh.y = [mesh.y midY-feed.width/2 midY+feed.width/2];
% add patch mesh with 2/3 - 1/3 rule
mesh.x = [mesh.x midX-patch.width/2-max_res/2*0.66 midX-patch.width/2+max_res/2*0.33 midX+patch.width/2+max_res/2*0.66 midX+patch.width/2-max_res/2*0.33];
% add patch mesh with 2/3 - 1/3 rule
mesh.y = [mesh.y midY-patch.length/2-max_res/2*0.66 midY-patch.length/2+max_res/2*0.33 midY+patch.length/2+max_res/2*0.66 midY+patch.length/2-max_res/2*0.33];
end
end
mesh.x = SmoothMeshLines( mesh.x, max_res, 1.4); % create a smooth mesh between specified mesh lines
mesh.y = SmoothMeshLines( mesh.y, 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 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);
%%
CSX = AddMetal( CSX, 'patch' ); % create a perfect electric conductor (PEC)
number = 1;
for xn=1:array.xn
for yn=1:array.yn
midX = (array.xn/2 - xn + 1/2) * array.x_spacing;
midY = (array.yn/2 - yn + 1/2) * array.y_spacing;
% create patch
start = [midX-patch.width/2 midY-patch.length/2 substrate.thickness];
stop = [midX+patch.width/2 midY+patch.length/2 substrate.thickness];
CSX = AddBox(CSX,'patch',10,start,stop);
% apply the excitation & resist as a current source
start = [midX+feed.pos midY-feed.width/2 0];
stop = [midX+feed.pos midY+feed.width/2 substrate.thickness];
[CSX port] = AddLumpedPort(CSX,number,feed.R, start, stop,[0 0 1],['excite_' int2str(xn) '_' int2str(yn)]);
number=number+1;
end
end
%%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}|' );
%%
number = 1;
P_in = 0;
for xn=1:array.xn
for yn=1:array.yn
U = ReadUI( ['port_ut' int2str(number)], 'tmp/', freq ); % time domain/freq domain voltage
I = ReadUI( ['port_it' int2str(number)], 'tmp/', freq ); % time domain/freq domain current (half time step is corrected)
P_in = P_in + 0.5*U.FD{1}.val .* conj( I.FD{1}.val );
number=number+1;
end
end
%% 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;
r = 1; % evaluate fields at radius r
disp( 'calculating far field at phi=[0 90] deg...' );
[E_far_theta,E_far_phi,Prad,Dmax] = AnalyzeNF2FF( Sim_Path, nf2ff, f_res, thetaRange, [0 90], r );
Dlog=10*log10(Dmax);
% display power and directivity
disp( ['radiated power: Prad = ' num2str(Prad) ' Watt']);
disp( ['directivity: Dmax = ' num2str(Dlog) ' dBi'] );
disp( ['efficiency: nu_rad = ' num2str(100*Prad./real(P_in(f_res_ind))) ' %']);
% calculate the e-field magnitude for phi = 0 deg
E_phi0_far = zeros(1,numel(thetaRange));
for n=1:numel(thetaRange)
E_phi0_far(n) = norm( [E_far_theta(n,1) E_far_phi(n,1)] );
end
E_phi0_far_log = 20*log10(abs(E_phi0_far)/max(abs(E_phi0_far)));
E_phi0_far_log = E_phi0_far_log + Dlog;
% display radiation pattern
figure
plot( thetaRange, E_phi0_far_log ,'k-' );
xlabel( 'theta (deg)' );
ylabel( 'directivity (dBi)');
grid on;
hold on;
% calculate the e-field magnitude for phi = 90 deg
E_phi90_far = zeros(1,numel(thetaRange));
for n=1:numel(thetaRange)
E_phi90_far(n) = norm([E_far_theta(n,2) E_far_phi(n,2)]);
end
E_phi90_far_log = 20*log10(abs(E_phi90_far)/max(abs(E_phi90_far)));
E_phi90_far_log = E_phi90_far_log + Dlog;
plot( thetaRange, E_phi90_far_log ,'r-' );
legend('phi=0','phi=90')
drawnow
if (draw_3d_pattern==0)
return
end
%% calculate 3D pattern
tic
phiRange = 0:3:360;
thetaRange = unique([0:0.5:15 10:3:180]);
r = 1; % evaluate fields at radius r
disp( 'calculating 3D far field...' );
[E_far_theta,E_far_phi] = AnalyzeNF2FF( Sim_Path, nf2ff, f_res, thetaRange, phiRange, r );
E_far = sqrt( abs(E_far_theta).^2 + abs(E_far_phi).^2 );
E_far_normalized = E_far / max(E_far(:)) * Dmax;
[theta,phi] = ndgrid(thetaRange/180*pi,phiRange/180*pi);
x = E_far_normalized .* sin(theta) .* cos(phi);
y = E_far_normalized .* sin(theta) .* sin(phi);
z = E_far_normalized .* cos(theta);
figure
surf( x,y,z, E_far_normalized );
axis equal
xlabel( 'x' );
ylabel( 'y' );
zlabel( 'z' );
toc
%% visualize magnetic fields
% you will find vtk dump files in the simulation folder (tmp/)
% use paraview to visulaize them