diff --git a/matlab/ReadHDF5Dump.m b/matlab/ReadHDF5Dump.m
index 3386971..9fc8c43 100644
--- a/matlab/ReadHDF5Dump.m
+++ b/matlab/ReadHDF5Dump.m
@@ -83,4 +83,10 @@ for n=1:2:(nargin-1)
             end
         end
     end
+end
+
+end
+
+function rng = range(x)
+    rng = max(x)-min(x);
 end
\ No newline at end of file
diff --git a/matlab/Tutorials/Patch_Antenna_Array.m b/matlab/Tutorials/Patch_Antenna_Array.m
index 83381ce..ed12c67 100644
--- a/matlab/Tutorials/Patch_Antenna_Array.m
+++ b/matlab/Tutorials/Patch_Antenna_Array.m
@@ -51,7 +51,7 @@ substrate.kappa  = 0.0013 * 2*pi*f0 * EPS0*substrate.epsR;
 substrate.thickness = 1.524;
 substrate.cells = 4;
 
-substrate.width = patch.W + range(xpos) + 4*patch.l;
+substrate.width = patch.W + max(xpos) - min(xpos) + 4*patch.l;
 substrate.length = 3*patch.l + patch.L;
 
 % size of the simulation box