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matlab: revision of AddMSLPort + calcPort 

all examples using this functions need to be revised!
pull/1/head
Thorsten Liebig 2011-09-19 10:14:27 +02:00
parent ed79f91a0f
commit dd7269d40a
3 changed files with 198 additions and 124 deletions
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156
matlab/AddMSLPort.m
View File

@ -1,38 +1,58 @@
function [CSX,port] = AddMSLPort( CSX, prio, portnr, materialname, start, stop, dir, evec, refplaneshift, excitename )
% [CSX,port] = AddMSLPort( CSX, prio, portnr, materialname, start, stop, dir, evec, refplaneshift, excitename )
function [CSX,port] = AddMSLPort( CSX, prio, portnr, materialname, start, stop, dir, evec, varargin )
% [CSX,port] = AddMSLPort( CSX, prio, portnr, materialname, start, stop, dir, evec, varargin )
%
% CSX: CSX-object created by InitCSX()
% prio: priority for excitation and probe boxes
% portnr: (integer) number of the port
% materialname: property for the MSL (created by AddMetal() or AddMaterial())
% materialname: property for the MSL (created by AddMetal())
% start: 3D start rowvector for port definition
% stop: 3D end rowvector for port definition
% dir: direction of wave propagation (choices: [1 0 0], [0 1 0] or [0 0 1])
% dir: direction of wave propagation (choices: 0 1 2)
% evec: excitation vector, which defines the direction of the e-field (must be the same as used in AddExcitation())
% refplaneshift (optional): if not specified or empty, the measurement
% plane is used; if specified, reference plane is shifted by
% <refplaneshift> starting from <start> (thus refplaneshift is normally
% positive)
% excitename (optional): if specified, the port will be switched on (see AddExcitation())
%
%
% variable input:
% 'ExcitePort' necessary excitation name to make the port an active feeding port
% 'FeedShift' shift to port from start by a given distance in drawing
% units. Default is 0. Only active if 'ExcitePort' is set!
% 'Feed_R' Specifiy a lumped port resistance. Default is no lumped
% port resistance --> port has to end in an ABC.
% Only active if 'ExcitePort' is set!
% 'MeasPlaneShift' Shift the measurement plane from start t a given distance
% in drawing units. Default is the middle of start/stop.
% Only active if 'ExcitePort' is set!
%
% the mesh must be already initialized
%
% example:
% start = [0 0 height]; stop = [length width 0]; dir = [1 0 0]; evec = [0 0 -1]
% this defines a MSL in x-direction (dir) with an e-field excitation in -z-direction (evec)
% the excitation is placed at x=start(1); the wave travels towards x=stop(1)
% the MSL-metal is created in xy-plane at z=start(3)
% start = [0 0 height];
% stop = [length width 0];
% CSX = AddMetal( CSX, 'metal' ); %create a PEC called 'metal'
% [CSX,port] = AddMSLPort( CSX, 0, 1, 'metal', start, stop, ...
% 0, [0 0 -1] , 'ExcitePort', 'excite', 'Feed_R', 50 )
%
% this defines a MSL in x-direction (dir=0) with an e-field excitation
% in -z-direction (evec=[0 0 -1]) the excitation is placed at x=start(1);
% the wave travels towards x=stop(1) the MSL-metal is created
% in xy-plane at z=start(3)
%
% Sebastian Held <sebastian.held@gmx.de>
% May 13 2010
% Sebastian Held <sebastian.held@gmx.de> May 13 2010
% Thorsten Liebig <thorsten.liebig@gmx.de> Sept 16 2011
%
% See also InitCSX AddMetal AddMaterial AddExcitation calcMSLPort
% See also InitCSX AddMetal AddMaterial AddExcitation calcPort
%% validate arguments %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%check mesh
if ~isfield(CSX,'RectilinearGrid')
error 'mesh needs to be defined! Use DefineRectGrid() first!';
if (~isfield(CSX.RectilinearGrid,'XLines') || ~isfield(CSX.RectilinearGrid,'YLines') || ~isfield(CSX.RectilinearGrid,'ZLines'))
error 'mesh needs to be defined! Use DefineRectGrid() first!';
end
end
% check dir
if ~(dir(1) == dir(2) == 0) && ~(dir(1) == dir(3) == 0) && ~(dir(2) == dir(3) == 0) || (sum(dir) == 0)
if ~( (dir >= 0) && (dir <= 2) )
error 'dir must have exactly one component ~= 0'
end
dir = dir ./ sum(dir); % dir is now a unit vector
% check evec
if ~(evec(1) == evec(2) == 0) && ~(evec(1) == evec(3) == 0) && ~(evec(2) == evec(3) == 0) || (sum(evec) == 0)
@ -40,14 +60,56 @@ if ~(evec(1) == evec(2) == 0) && ~(evec(1) == evec(3) == 0) && ~(evec(2) == evec
end
evec0 = evec ./ sum(evec); % evec0 is a unit vector
%% read optional arguments %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
n_conv_arg = 8; % number of conventional arguments
%set defaults
feed_shift = 0;
feed_R = 0;
excitename = '';
measplanepos = nan;
if (nargin>n_conv_arg)
for n=1:2:(nargin-n_conv_arg)
if (strcmp(varargin{n},'FeedShift')==1);
feed_shift = varargin{n+1};
if (numel(feed_shift)>1)
error 'FeedShift must be a scalar value'
end
end
if (strcmp(varargin{n},'Feed_R')==1);
feed_R = varargin{n+1};
if (numel(feed_shift)>1)
error 'Feed_R must be a scalar value'
end
end
if (strcmp(varargin{n},'MeasPlaneShift')==1);
measplanepos = varargin{n+1};
if (numel(feed_shift)>1)
error 'MeasPlaneShift must be a scalar value'
end
end
if (strcmp(varargin{n},'ExcitePort')==1);
excitename = varargin{n+1};
end
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% normalize start and stop
nstart = min( [start;stop] );
nstop = max( [start;stop] );
% determine index (1, 2 or 3) of propagation (length of MSL)
idx_prop = dir * [1;2;3];
idx_prop = dir + 1;
% determine index (1, 2 or 3) of width of MSL
dir = [0 0 0];
dir(idx_prop) = 1;
idx_width = abs(cross(dir,evec0)) * [1;2;3];
% determine index (1, 2 or 3) of height
@ -66,14 +128,17 @@ MSL_stop = stop;
MSL_stop(idx_height) = MSL_start(idx_height);
CSX = AddBox( CSX, materialname, prio, MSL_start, MSL_stop );
% FIXME
% openEMS v0.0.7 does not snap PEC
if isnan(measplanepos)
measplanepos = (nstart(idx_prop)+nstop(idx_prop))/2;
else
measplanepos = start(idx_prop)+direction*measplanepos;
end
% calculate position of the voltage probes
mesh{1} = sort(CSX.RectilinearGrid.XLines);
mesh{2} = sort(CSX.RectilinearGrid.YLines);
mesh{3} = sort(CSX.RectilinearGrid.ZLines);
meshlines = interp1( mesh{idx_prop}, 1:numel(mesh{idx_prop}), (nstart(idx_prop)+nstop(idx_prop))/2, 'nearest' );
meshlines = interp1( mesh{idx_prop}, 1:numel(mesh{idx_prop}), measplanepos, 'nearest' );
meshlines = mesh{idx_prop}(meshlines-1:meshlines+1); % get three lines (approx. at center)
if direction == -1
meshlines = fliplr(meshlines);
@ -82,9 +147,9 @@ MSL_w2 = interp1( mesh{idx_width}, 1:numel(mesh{idx_width}), (nstart(idx_width)+
MSL_w2 = mesh{idx_width}(MSL_w2); % get e-line at center of MSL (MSL_width/2)
v1_start(idx_prop) = meshlines(1);
v1_start(idx_width) = MSL_w2;
v1_start(idx_height) = nstop(idx_height);
v1_start(idx_height) = start(idx_height);
v1_stop = v1_start;
v1_stop(idx_height) = nstart(idx_height);
v1_stop(idx_height) = stop(idx_height);
v2_start = v1_start;
v2_stop = v1_stop;
v2_start(idx_prop) = meshlines(2);
@ -111,7 +176,8 @@ i2_stop(idx_prop) = i2_start(idx_prop);
% create the probes
name = ['port_ut' num2str(portnr) 'A'];
weight = sum(evec);
% weight = sign(stop(idx_height)-start(idx_height))
weight = -1;
CSX = AddProbe( CSX, name, 0, weight );
CSX = AddBox( CSX, name, prio, v1_start, v1_stop );
name = ['port_ut' num2str(portnr) 'B'];
@ -121,7 +187,8 @@ name = ['port_ut' num2str(portnr) 'C'];
CSX = AddProbe( CSX, name, 0, weight );
CSX = AddBox( CSX, name, prio, v3_start, v3_stop );
name = ['port_it' num2str(portnr) 'A'];
weight = direction;
weight = direction
CSX = AddProbe( CSX, name, 1, weight );
CSX = AddBox( CSX, name, prio, i1_start, i1_stop );
name = ['port_it' num2str(portnr) 'B'];
@ -131,41 +198,18 @@ CSX = AddBox( CSX, name, prio, i2_start, i2_stop );
% create port structure
port.nr = portnr;
port.drawingunit = CSX.RectilinearGrid.ATTRIBUTE.DeltaUnit;
% port.start = start;
% port.stop = stop;
% port.v1_start = v1_start;
% port.v1_stop = v1_stop;
% port.v2_start = v2_start;
% port.v2_stop = v2_stop;
% port.v3_start = v3_start;
% port.v3_stop = v3_stop;
port.v_delta = diff(meshlines);
% port.i1_start = i1_start;
% port.i1_stop = i1_stop;
% port.i2_start = i2_start;
% port.i2_stop = i2_stop;
port.i_delta = diff( meshlines(1:end-1) + diff(meshlines)/2 );
port.direction = direction;
% port.dir = dir;
% port.evec = evec;
% port.idx_prop = idx_prop;
% port.idx_width = idx_width;
% port.idx_height = idx_height;
port.excite = 0;
port.refplaneshift = 0;
port.measplanepos = abs(v2_start(idx_prop) - start(idx_prop));
if (nargin >= 9) && (~isempty(refplaneshift))
% refplaneshift counts from start of port
port.refplaneshift = refplaneshift - direction*(v2_start(idx_prop) - start(idx_prop));
end
% create excitation
if nargin >= 10
if ~isempty(excitename)
% excitation of this port is enabled
port.excite = 1;
meshline = interp1( mesh{idx_prop}, 1:numel(mesh{idx_prop}), start(idx_prop), 'nearest' );
ex_start(idx_prop) = mesh{idx_prop}(meshline+direction);
meshline = interp1( mesh{idx_prop}, 1:numel(mesh{idx_prop}), start(idx_prop) + feed_shift*direction, 'nearest' );
ex_start(idx_prop) = mesh{idx_prop}(meshline) ;
ex_start(idx_width) = nstart(idx_width);
ex_start(idx_height) = nstart(idx_height);
ex_stop(idx_prop) = ex_start(idx_prop);
@ -173,4 +217,10 @@ if nargin >= 10
ex_stop(idx_height) = nstop(idx_height);
CSX = AddExcitation( CSX, excitename, 0, evec );
CSX = AddBox( CSX, excitename, prio, ex_start, ex_stop );
if feed_R > 0
CSX = AddLumpedElement( CSX, [excitename '_R'], idx_height-1, 'R', feed_R );
CSX = AddBox( CSX, [excitename '_R'], prio, ex_start, ex_stop );
port.Feed_R = port_R;
end
end

153
matlab/calcPort.m
View File

@ -1,24 +1,34 @@
function [S11,beta,ZL,vi] = calcPort( portstruct, SimDir, f, ref_shift )
%[S11,beta,ZL,vi] = calcPort( portstruct, SimDir, [f], [ref_shift] )
function [port] = calcPort( port, SimDir, f, varargin)
% [port] = calcPort( port, SimDir, f, [ref_ZL], [ref_shift])
%
% Calculate the reflection coefficient S11, the propagation constant beta
% of the MSL-port and the characteristic impedance ZL of the MSL-port.
% The port is to be created by AddMSLPort().
% Calculate voltages and currents, the propagation constant beta
% and the characteristic impedance ZL of the given port.
% The port has to be created by e.g. AddMSLPort().
%
% input:
% portstruct: return value of AddMSLPort()
% port: return value of AddMSLPort()
% SimDir: directory, where the simulation files are
% f: (optional) frequency vector for DFT
% ref_shift: (optional) reference plane shift measured from start of port (in drawing units)
% f: frequency vector for DFT
%
% variable input:
% 'RefImpedance': use a given reference impedance to calculate inc and
% ref voltages and currents
% default is given port or calculated line impedance
% 'RefPlaneShift': use a given reference plane shift from port beginning
% for a desired phase correction
% default is the measurement plane
%
% output:
% S11: reflection coefficient (normalized to ZL)
% beta: propagation constant
% ZL: characteristic line impedance
% vi: structure of voltages and currents
% vi.TD.v.{val,t}; vi.TD.i.{val,t};
% vi.FD.v.{val,val_shifted,f}; vi.FD.i.{val,val_shifted,f};
% output:
% port.f the given frequency fector
% port.uf.tot/inc/ref total, incoming and reflected voltage
% port.if.tot/inc/ref total, incoming and reflected current
% port.beta: propagation constant
% port.ZL: characteristic line impedance
%
% example:
% port{1} = calcPort( port{1}, Sim_Path, f, 'RefImpedance', 50);
% or
%
% reference: W. K. Gwarek, "A Differential Method of Reflection Coefficient Extraction From FDTD Simulations",
% IEEE Microwave and Guided Wave Letters, Vol. 6, No. 5, May 1996
%
@ -28,83 +38,96 @@ function [S11,beta,ZL,vi] = calcPort( portstruct, SimDir, f, ref_shift )
% See also AddMSLPort
%DEBUG
% save('/tmp/test.mat', 'portstruct', 'SimDir', 'f', 'nargin' )
% save('/tmp/test.mat', 'port', 'SimDir', 'f', 'nargin' )
% load('/tmp/test.mat')
% check
if portstruct.v_delta(1) ~= portstruct.v_delta(2)
if abs((port.v_delta(1) - port.v_delta(2)) / port.v_delta(1))>1e-6
warning( 'openEMS:calcPort:mesh', 'mesh is not equidistant; expect degraded accuracy' );
end
if nargin < 3
f = [];
%% read optional arguments %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
n_conv_arg = 3; % number of conventional arguments
%set defaults
ref_ZL = 0;
ref_shift = nan;
if (nargin>n_conv_arg)
for n=1:2:(nargin-n_conv_arg)
if (strcmp(varargin{n},'RefPlaneShift')==1);
ref_shift = varargin{n+1};
end
if (strcmp(varargin{n},'RefImpedance')==1);
ref_ZL = varargin{n+1};
end
end
end
% read time domain data
filename = ['port_ut' num2str(portstruct.nr)];
filename = ['port_ut' num2str(port.nr)];
U = ReadUI( {[filename 'A'],[filename 'B'],[filename 'C']}, SimDir, f );
filename = ['port_it' num2str(portstruct.nr)];
filename = ['port_it' num2str(port.nr)];
I = ReadUI( {[filename 'A'],[filename 'B']}, SimDir, f );
% store the original time domain waveforms
vi.TD.v = U.TD{2};
vi.TD.i.t = I.TD{1}.t;
vi.TD.i.val = (I.TD{1}.val + I.TD{2}.val) / 2; % shift to same position as v
% store the original frequency domain waveforms
vi.FD.v = U.FD{2};
vi.FD.i = I.FD{1};
vi.FD.i.val = (I.FD{1}.val + I.FD{2}.val) / 2; % shift to same position as v
u_f = U.FD{2}.val;
i_f = (I.FD{1}.val + I.FD{2}.val) / 2; % shift to same position as v
f = U.FD{2}.f;
Et = U.FD{2}.val;
dEt = (U.FD{3}.val - U.FD{1}.val) / (sum(abs(portstruct.v_delta(1:2))) * portstruct.drawingunit);
dEt = (U.FD{3}.val - U.FD{1}.val) / (sum(abs(port.v_delta(1:2))) * port.drawingunit);
Ht = (I.FD{1}.val + I.FD{2}.val)/2; % space averaging: Ht is now defined at the same pos as Et
dHt = (I.FD{2}.val - I.FD{1}.val) / (abs(portstruct.i_delta(1)) * portstruct.drawingunit);
dHt = (I.FD{2}.val - I.FD{1}.val) / (abs(port.i_delta(1)) * port.drawingunit);
beta = sqrt( - dEt .* dHt ./ (Ht .* Et) );
beta(real(beta) < 0) = -beta(real(beta) < 0); % determine correct sign (unlike the paper)
% determine S11
A = sqrt( Et .* dHt ./ (Ht .* dEt) );
A(imag(A) > 0) = -A(imag(A) > 0); % determine correct sign (unlike the paper)
S11 = (A - 1) ./ (A + 1);
% determine S11_corrected
delta_e = sum(portstruct.v_delta(1:2))/2 * portstruct.drawingunit;
delta_h = portstruct.i_delta(1) * portstruct.drawingunit;
S11_corrected = sqrt( Et .* (dHt ./ (sin(beta.*delta_h*.5)/(beta*delta_h*.5))) ./ ((Ht ./ cos(beta*delta_h*.5)) .* (dEt ./ (sin(beta*delta_e)./(beta*delta_e)))));
S11_corrected(imag(S11_corrected) > 0) = -S11_corrected(imag(S11_corrected) > 0); % determine correct sign (unlike the paper)
S11_corrected = (S11_corrected-1) ./ (S11_corrected+1);
% my own solution...
temp = sqrt(-dHt .* dEt ./ (Ht .* Et));
S11 = (-1i * dEt + Et .* temp) ./ (Et .* temp + 1i * dEt); % solution 1
% S11 = (-1i * dEt - Et .* temp) ./ (-Et .* temp + 1i * dEt); % solution 2
% % determine ZL
% Et_forward = Et ./ (1 + S11);
% Ht_forward = Ht ./ (1 - S11);
% ZL = Et_forward ./ Ht_forward;
%
% % determine ZL_corrected
% Et_forward_corrected = Et ./ (1 + S11_corrected);
% Ht_forward_corrected = Ht ./ (1 - S11_corrected);
% ZL_corrected = Et_forward_corrected ./ Ht_forward_corrected;
% determine ZL
ZL = sqrt(Et .* dEt ./ (Ht .* dHt));
% reference plane shift (lossless)
if (nargin > 3)
if ~isnan(ref_shift)
% renormalize the shift to the measurement plane
ref_shift = ref_shift - portstruct.measplanepos;
ref_shift = ref_shift * portstruct.drawingunit;
S11 = S11 .* exp(2i*real(beta)*ref_shift);
S11_corrected = S11_corrected .* exp(2i*real(beta)*ref_shift);
ref_shift = ref_shift - port.measplanepos * port.drawingunit;
% ref_shift = ref_shift * port.drawingunit;
% store the shifted frequency domain waveforms
phase = real(beta)*ref_shift;
vi.FD.v.val_shifted = vi.FD.v.val .* cos(-phase) + 1i * vi.FD.i.val.*ZL .* sin(-phase);
vi.FD.i.val_shifted = vi.FD.i.val .* cos(-phase) + 1i * vi.FD.v.val./ZL .* sin(-phase);
U.FD{1}.val = u_f .* cos(-phase) + 1i * i_f.*ZL .* sin(-phase);
I.FD{1}.val = i_f .* cos(-phase) + 1i * u_f./ZL .* sin(-phase);
u_f = U.FD{1}.val;
i_f = I.FD{1}.val;
end
if (ref_ZL == 0)
if isfield(port,'Feed_R')
ref_ZL = port.Feed_R;
else
ref_ZL = ZL;
end
end
port.ZL = ZL;
port.beta = beta;
port.f = f;
uf_inc = 0.5 * ( u_f + i_f .* ref_ZL );
if_inc = 0.5 * ( i_f + u_f ./ ref_ZL );
uf_ref = u_f - uf_inc;
if_ref = if_inc - i_f;
port.uf.tot = u_f;
port.uf.inc = uf_inc;
port.uf.ref = uf_ref;
port.if.tot = i_f;
port.if.inc = if_inc;
port.if.ref = if_ref;
port.raw.U = U;
port.raw.I = I;

13
matlab/examples/microstrip/MSL2.m → matlab/examples/__deprecated__/MSL2.m
View File

@ -53,7 +53,7 @@ min_decrement = 1e-6;
f_max = 7e9;
FDTD = InitFDTD( max_timesteps, min_decrement, 'OverSampling', 10 );
FDTD = SetGaussExcite( FDTD, f_max/2, f_max/2 );
BC = {'MUR' 'PEC' 'PEC' 'PEC' 'PEC' 'PMC'};
BC = {'MUR' 'MUR' 'PEC' 'PEC' 'PEC' 'PMC'};
FDTD = SetBoundaryCond( FDTD, BC );
%% setup CSXCAD geometry & mesh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@ -161,9 +161,9 @@ grid on
title( 'Frequency domain current probes' );
legend( {'abs(if1A)','abs(if1B)','angle(if1A)','angle(if1B)'} );
% port analysis
[S11,beta,ZL,vi] = calcPort( portstruct, Sim_Path, f );
% attention! the reflection coefficient S11 is normalized to ZL!
%% port analysis
[U,I,beta,ZL] = calcPort( portstruct, Sim_Path, f );
%% attention! the reflection coefficient S11 is normalized to ZL!
figure
plot( sin(0:0.01:2*pi), cos(0:0.01:2*pi), 'Color', [.7 .7 .7] );
@ -216,9 +216,10 @@ grid on;
legend( {'real','imaginary'}, 'location', 'northeast' )
title( 'Characteristic line impedance ZL' );
% reference plane shift (to the end of the port)
%% reference plane shift (to the end of the port)
ref_shift = abs(portstop(1) - portstart(1));
[S11,beta,ZL,vi] = calcPort( portstruct, Sim_Path, f, ref_shift );
[U, I,beta,ZL] = calcPort( portstruct, Sim_Path, f );
%%
figure
plotyy( f/1e9, 20*log10(abs(S11)), f/1e9, angle(S11)/pi*180 );