Restructuring some of the docs.

docs/source/user_libraries.rst

@@ -0,0 +1,34 @@
+.. _user-libs:
+
+*************
+User libaries
+*************
+
+The user libraries sub-package is where useful modules contributed by users are stored.
+
+antennas.py
+===========
+
+This library currently features models of antennas similar to:
+
+* a Geophysical Survey Systems, Inc. (GSSI) 1.5 GHz (Model 5100) antenna (http://www.geophysical.com)
+* a MALA Geoscience 1.2 GHz antenna (http://www.malags.com/)
+
+These antenna models can be accessed from within a block of Python code in your simulation. For example, to use Python to include an antenna model similar to a GSSI 1.5 GHz antenna at a location 0.125m, 0.094m, 0.100m (x,y,z) using a 1mm spatial resolution:
+
+.. code-block:: none
+
+    #python:
+    from user_libs.antennas import antenna_like_GSSI_1500
+    antenna_like_GSSI_1500(0.125, 0.094, 0.100, 0.001)
+    #end_python:
+
+.. figure:: images/antenna_like_MALA_1200.png
+    :width: 600 px
+
+    FDTD geometry mesh showing an antenna model similar to a MALA 1.2GHz antenna (skid removed for illustrative purposes).
+
+.. figure:: images/antenna_like_GSSI_1500.png
+    :width: 600 px
+
+    FDTD geometry mesh showing an antenna model similar to a GSSI 1.5GHz antenna (skid removed for illustrative purposes).