The instantaneous luminosity of the Large Hadron Collider at CERN will
be increased by about a factor of five with respect to the design value by an
extensive upgrade program over the coming decade. The largest Phase-1 upgrade
project for the ATLAS Muon System is the replacement of the present inner
station in the forward regions with the New Small Wheels (NSWs) during the
long LHC shutdown in 2019/20. Along with Micromegas, the NSWs will be equipped
with eight layers of small-strip Thin Gap Chambers (sTGC) arranged in
multilayers of two quadruplets. To retain the good precision tracking and
trigger capabilities in the high-background environment of the high luminosity
LHC, each sTGC plane must achieve a spatial resolution better than 100~μm
to allow the Level-1 trigger track segments to be reconstructed with an
angular resolution of approximately 1~mrad. The sTGC design, performance,
construction and integration status will be discussed, along with results from
tests of the chambers with nearly final electronics with beams
and high-intensity radiation sources.