Construction and quality assurance of large area resistive strip MicroMegas for the upgrade of the ATLAS muon spectrometer.
The current innermost station of the muon end-cap system (Small Wheel) will be upgraded during the 2019-2020 LHC long shutdown. Large-size multilayer resistive MicroMegas detectors will be employed. In order to achieve 15% transverse-momentum resolution for 1 TeV muons each active plane has to provide a spatial resolution of about 100 $\mu$m, and a construction accuracy allowing an extreme and challenging alignment of the readout elements. In this presentation, the construction procedures and quality assurance tests of the first two full-size prototypes will be reviewed along with the performance results obtained using 180 GeV/$c$ pions produced at the CERN-SPS test beam facility and cosmic ray muons.