New upstream version 0.0.35+ds.1

1 files changed, 145 insertions, 0 deletions

diff --git a/openEMS/matlab/plotRefl.m b/openEMS/matlab/plotRefl.m
new file mode 100644
index 0000000..5f88631
--- /dev/null
+++ b/openEMS/matlab/plotRefl.m
@@ -0,0 +1,145 @@
+function h = plotRefl(port, varargin) 

+

+%  h = plotRefl(port,varargin)

+%

+%  plot the reflection coefficient of a port into a Smith chart.

+%  left and right facing triangles mark the lower and upper cutoff

+%  frequency of the pass bands. An asterisk marks the frequnecy with 

+%  the lowest reflection.

+%

+% input:

+%   port:      port data structure. Call calcPort with an appropriate 

+%              frequency vector before calling this routine

+% 

+% output:      graphics handle for further modification of the plot.

+%

+% variable input:

+%   'precision':   - number of decimal places (floating point precision) 

+%                    for the frequency (always in MHz), default is 0

+%   'threshold':   - Threshold value (in dB) for the upper and lower

+%                    cutoff frequency, default is -3

+%   example:

+%       myport = calcPort(myport, Sim_Path, linspace(f_0-f_c, f_0+f_c, 200));

+%       plotRefl(myport);

+%

+% See also calcPort

+% 

+% openEMS matlab interface

+% -----------------------

+% author: Georg Michel

+

+%defaults

+precision = 0;

+threshold = -3;

+

+

+for n=1:2:numel(varargin)

+    if (strcmp(varargin{n},'precision')==1);

+        precision = varargin{n+1};

+    elseif (strcmp(varargin{n},'threshold')==1);

+        threshold = varargin{n+1};

+    else

+        warning('openEMS:polarFF',['unknown argument key: ''' varargin{n} '''']);

+    end

+end

+

+

+if ~isfield(port, 'uf')

+  error('Cannot plot the reflection coefficient. Please call calcPort first.');

+end

+

+s11 = port.uf.ref ./ port.uf.inc;

+ffmt = ['%.', num2str(precision), 'f'];

+

+

+

+figure; %new figure

+

+plot([-1, 1], [0, 0], 'k');

+

+

+axis ([-1.15, 1.15, -1.15, 1.15], "square");

+axis off;

+hold on

+

+ReZ = [.2; .5; 1; 2]; 

+ImZ = 1i * [1 2 5 2];

+Z = bsxfun(@plus, ReZ, linspace(-ImZ, ImZ, 256));

+Gamma = (Z-1)./(Z+1);

+plot(Gamma.', 'k');

+

+ReZ = [.5 .5 1 1 2 2 5 5 10 10];

+ImZ = 1i * [-.2; .2; -.5; .5; -1; 1; -2; 2; -5; 5];

+Z = bsxfun(@plus, linspace(0, ReZ, 256), ImZ);

+Gamma = (Z-1)./(Z+1);

+plot(Gamma.', 'k');

+

+

+angle = linspace (0, 2 * pi, 256); ReZ = [0 5 10];

+center = ReZ ./ (ReZ + 1);

+radius = 1 ./ (ReZ + 1);

+plot(bsxfun(@plus, bsxfun(@times, radius, cos(angle.')), center), bsxfun(@times, radius, sin(angle.')), 'k');

+

+

+% resistance

+ReZ = [0.2 0.5 1 2 5 10]; ImZ = zeros (1, length (ReZ));

+rho = (ReZ.^2 + ImZ.^2 - 1 + 2i * ImZ) ./ ((ReZ + 1).^2 + ImZ.^2);

+

+xoffset = [0.1 0.1 0.05 0.05 0.05 0.075]; 

+yoffset = -0.03;

+

+for idx = 1:length (ReZ)

+    text (real (rho(idx)) - xoffset(idx), ...

+        imag (rho(idx)) - yoffset, num2str (ReZ(idx)));

+end

+

+% reactance

+ReZ = [-0.06 -0.06 -0.06 -0.12 -0.5];

+ImZ = [0.2 0.5 1 2 5];

+

+

+rho = (ReZ.^2 + ImZ.^2 - 1 + 2i * ImZ) ./ ((ReZ + 1).^2 + ImZ.^2);

+

+for idx = 1:length (ImZ)

+    text (real (rho(idx)), imag (rho(idx)), [num2str(ImZ(idx)), "j"]);

+    text (real (rho(idx)), -imag (rho(idx)), [num2str(-ImZ(idx)), "j"]); end

+

+% zero

+rho = (-0.05.^2 + 0.^2 - 1) ./ ((-0.05 + 1).^2 + 0.^2);

+

+text (real (rho), imag (rho), '0');

+

+s11dB = 20*log10(abs(s11));

+

+upperind = s11dB(1:end-1) < threshold & s11dB(2:end) > threshold;

+lowerind = s11dB(1:end-1) > threshold & s11dB(2:end) < threshold;

+minind = nthargout(2, @min, s11dB);

+handle1 = plot(s11(lowerind),['<','b']);

+handle2 = plot(s11(upperind),['>','b']);

+handle3 = plot(s11(minind),['*', 'b']);

+llegend = num2str(port.f(lowerind)(1)/1e6, ffmt);

+ulegend = num2str(port.f(upperind)(1)/1e6, ffmt);

+

+if nnz(lowerind) > 1

+  for i= 2:nnz(lowerind)

+    llegend = strjoin({llegend, num2str(port.f(lowerind)(i)/1e6, ffmt)}, ', ');

+  end

+end

+

+if nnz(upperind) > 1

+  for i= 2:nnz(upperind)

+    ulegend = strjoin({ulegend, num2str(port.f(upperind)(i)/1e6, ffmt)}, ', ');

+  end

+end

+

+legend([handle1, handle2, handle3], {[llegend, " MHz"], ...

+                                     [ulegend, " MHz"], ...

+                                     [num2str(20*log10(abs(s11(minind))), "%4.0f"), ...

+                                    "dB @ ", num2str(port.f(minind)/1e6, ffmt), " MHz"]});

+h = plot(s11);

+

+if (nargout == 0)

+  clear h;

+end

+

+end
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