ForumNG:Advanced search across Forums

Bug 11276
Course-pres: B201-10B
Logged in as: md5327/testing

I searched in the Author Name field with the following
SANJANA
SAN
JANA MATHEW
MATHEW
It all gave me appropriate results for me as the author.

However if I searched for JANA or THEW which are finishing characters of my
name and surname it did not give any results.
I wonder why it searches for JANA MATHEW which is also in a sense trailing
characters of my whole name but does not search for trailing characters of
forename or surname individually.