Merge commit 'upstream/4.6.1'

[debian/atlc] / src / calculate_Zodd_and_Zeven.c

diff --git a/src/calculate_Zodd_and_Zeven.c b/src/calculate_Zodd_and_Zeven.c
new file mode 100644 (file)
index 0000000..d6db981
--- /dev/null
+++ b/src/calculate_Zodd_and_Zeven.c
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+/* atlc - arbitrary transmission line calculator, for the analysis of
+transmission lines are directional couplers. 
+
+Copyright (C) 2002. Dr. David Kirkby, PhD (G8WRB).
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either package_version 2
+of the License, or (at your option) any later package_version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+USA.
+
+Dr. David Kirkby, e-mail drkirkby at gmail.com 
+
+*/
+
+/* The following calculates the odd and even mode impedances between two
+zero thickness strips of width w, spaced a distance s between two
+groundplanes of spacing h. */
+
+#include "config.h"
+
+#include "gsl_types.h"
+#include "gsl_definitions.h"
+#include "definitions.h"
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#ifdef HAVE_MATH_H
+#include <math.h>
+#endif
+
+#include "exit_codes.h"
+/* formuals taken from Matthaei, Young and Jones, Microwave Filters, Impedance Matching
+Networks and Coupling Structures, Artech House, Dedham, MA., 1980. , but I've substituted
+29.97924580105028, as its clear 30 is just a close approximation */
+
+void calculate_Zodd_and_Zeven(double *Zodd, double *Zeven, double *Zo, double w, double H, double s, double er)
+{
+  double ke, ko, ko_dash, ke_dash;
+  ke=(tanh((M_PI/2)*(w/H)))*tanh((M_PI/2)*(w+s)/H);
+  ko=(tanh((M_PI/2)*(w/H)))/tanh((M_PI/2)*(w+s)/H);
+
+  ke_dash=sqrt(1-ke*ke);
+  ko_dash=sqrt(1-ko*ko);
+
+  *Zeven=29.9792458010502837*M_PI*gsl_sf_ellint_Kcomp(ke_dash, GSL_PREC_DOUBLE)/(gsl_sf_ellint_Kcomp(ke,GSL_PREC_DOUBLE)*sqrt(er));
+  *Zodd= 29.9792458010502837*M_PI*gsl_sf_ellint_Kcomp(ko_dash, GSL_PREC_DOUBLE)/(gsl_sf_ellint_Kcomp(ko,GSL_PREC_DOUBLE)*sqrt(er));
+  *Zo=sqrt( (*Zodd)*(*Zeven));
+}