Updated titles of some examples.

docs/source/examples_3D.rst

@@ -4,8 +4,8 @@
 
 This section provides some general example models in 3D that demonstrate how to use certain features of gprMax. Each example comes with an input file which you can download and run.
 
-Using an antenna model
-======================
+Bowtie antenna model
+====================
 
 :download:`antenna_MALA_1200_fs.in <models/antenna_MALA_1200_fs.in>`