We report on the deposition of nanocrystalline diamond films onto protected aluminum/pyrex glass mirrors in focused or linear antenna microwave plasma enhanced chemical vapour deposition systems. Quality of the diamond films is characterized by Raman spectroscopy, scanning electron microscopy and optical images. The best material quality and coating uniformity is achieved in the linear antenna system. Infrared reflectance spectroscopy reveals enhanced reflection from the substrates prepared in the linear antenna system compared to diamond coatings prepared in common focused plasma system on protected aluminium/pyrex glass mirrors as well as on polished Si wafers. Linear antenna system diamond coatings are thus the most promising for spectroscopic characterization of molecular grafting to diamond. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim