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diff --git a/openEMS/python/Tutorials/Rect_Waveguide.py b/openEMS/python/Tutorials/Rect_Waveguide.py
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+++ b/openEMS/python/Tutorials/Rect_Waveguide.py
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+# -*- coding: utf-8 -*-
+"""
+ Rectangular Waveguide Tutorial
+
+ Describtion at:
+ http://openems.de/doc/openEMS/Tutorials.html#rectangular-waveguide
+
+ Tested with
+  - python 3.4
+  - openEMS v0.0.34+
+
+ (C) 2015-2016 Thorsten Liebig <thorsten.liebig@gmx.de>
+
+"""
+
+### Import Libraries
+import os, tempfile
+from pylab import *
+
+from CSXCAD  import ContinuousStructure
+from openEMS import openEMS
+from openEMS.physical_constants import *
+
+### Setup the simulation
+Sim_Path = os.path.join(tempfile.gettempdir(), 'Rect_WG')
+
+post_proc_only = False
+unit = 1e-6; #drawing unit in um
+
+# waveguide dimensions
+# WR42
+a = 10700;   #waveguide width
+b = 4300;    #waveguide heigth
+length = 50000;
+
+# frequency range of interest
+f_start = 20e9;
+f_0     = 24e9;
+f_stop  = 26e9;
+lambda0 = C0/f_0/unit;
+
+#waveguide TE-mode definition
+TE_mode = 'TE10';
+
+#targeted mesh resolution
+mesh_res = lambda0/30
+
+### Setup FDTD parameter & excitation function
+FDTD = openEMS(NrTS=1e4);
+FDTD.SetGaussExcite(0.5*(f_start+f_stop),0.5*(f_stop-f_start));
+
+# boundary conditions
+FDTD.SetBoundaryCond([0, 0, 0, 0, 3, 3]);
+
+### Setup geometry & mesh
+CSX = ContinuousStructure()
+FDTD.SetCSX(CSX)
+mesh = CSX.GetGrid()
+mesh.SetDeltaUnit(unit)
+
+mesh.AddLine('x', [0, a])
+mesh.AddLine('y', [0, b])
+mesh.AddLine('z', [0, length])
+
+## Apply the waveguide port
+ports = []
+start=[0, 0, 10*mesh_res];
+stop =[a, b, 15*mesh_res];
+mesh.AddLine('z', [start[2], stop[2]])
+ports.append(FDTD.AddRectWaveGuidePort( 0, start, stop, 'z', a*unit, b*unit, TE_mode, 1))
+
+start=[0, 0, length-10*mesh_res];
+stop =[a, b, length-15*mesh_res];
+mesh.AddLine('z', [start[2], stop[2]])
+ports.append(FDTD.AddRectWaveGuidePort( 1, start, stop, 'z', a*unit, b*unit, TE_mode))
+
+mesh.SmoothMeshLines('all', mesh_res, ratio=1.4)
+
+### Define dump box...
+Et = CSX.AddDump('Et', file_type=0, sub_sampling=[2,2,2])
+start = [0, 0, 0];
+stop  = [a, b, length];
+Et.AddBox(start, stop);
+
+### Run the simulation
+if 0:  # debugging only
+    CSX_file = os.path.join(Sim_Path, 'rect_wg.xml')
+    if not os.path.exists(Sim_Path):
+        os.mkdir(Sim_Path)
+    CSX.Write2XML(CSX_file)
+    os.system(r'AppCSXCAD "{}"'.format(CSX_file))
+
+if not post_proc_only:
+    FDTD.Run(Sim_Path, verbose=3, cleanup=True)
+
+### Postprocessing & plotting
+freq = linspace(f_start,f_stop,201)
+for port in ports:
+    port.CalcPort(Sim_Path, freq)
+
+s11 = ports[0].uf_ref / ports[0].uf_inc
+s21 = ports[1].uf_ref / ports[0].uf_inc
+ZL  = ports[0].uf_tot / ports[0].if_tot
+ZL_a = ports[0].ZL # analytic waveguide impedance
+
+## Plot s-parameter
+figure()
+plot(freq*1e-6,20*log10(abs(s11)),'k-',linewidth=2, label='$S_{11}$')
+grid()
+plot(freq*1e-6,20*log10(abs(s21)),'r--',linewidth=2, label='$S_{21}$')
+legend();
+ylabel('S-Parameter (dB)')
+xlabel(r'frequency (MHz) $\rightarrow$')
+
+## Compare analytic and numerical wave-impedance
+figure()
+plot(freq*1e-6,real(ZL), linewidth=2, label='$\Re\{Z_L\}$')
+grid()
+plot(freq*1e-6,imag(ZL),'r--', linewidth=2, label='$\Im\{Z_L\}$')
+plot(freq*1e-6,ZL_a,'g-.',linewidth=2, label='$Z_{L, analytic}$')
+ylabel('ZL $(\Omega)$')
+xlabel(r'frequency (MHz) $\rightarrow$')
+legend()
+
+show()