The invention relates to a microwave arrangement for the transmission of high-frequency signals of high powers comprising a microstrip conductor on an upper side of a substrate. The microstrip line comprises a multi-stage signal splitter and a ground surface on an underside of the substrate disposed opposite to the upper side. A defected ground structure is introduced into the ground-surface below a first stage of the signal splitter. Further a power combiner and/or a power splitter with a microwave arrangement according to example embodiments of the invention.