An arrangement for coupling microwave energy into a plasma CVD coating chamber (3) disposed in a cavity resonator (1) has a microwave feed (11) and a microwave waveguide (9, 1). So that a plastic container of a size and configuration which differ to a certain degree can be effectively coated in its interior, it is provided that the arrangement is of a substantially cylindrical structure, such that provided at the rear end is a first coaxial waveguide (in the region a) with an internal conductor in the form of an antenna (12), an approximately cylindrical waveguide (in the region b) follows in the centre of the arrangement and provided at the front end (in the region c) is a second coaxial waveguide (1) with internal conductor (13), wherein gas can be introduced through a gas feed tube (13) into the second coaxial waveguide (in the region c), which gas can be activated into the plasma state by the coupled-in microwave energy, and wherein a TM-mode is produced by the antenna (12) in the plasma region (1, c).