Magnetron sputter deposition is a widely used tool for the deposition of high-quality functional thin lms on industrially relevant objects. A magnetic conguration modies the plasma-formation in a favorable way for the desired application. Often this happens by the concentration of the plasma-discharge at specic target-areas. This leads to higher ecffiency compared to conventional sputtering using the same parameters. For some applications, magnetrons are the key to enable the applicability of this Physical Vapor Deposition (PVD) process. The rst part of this thesis consisted of the modication of an existing cylindrical magnetron. This happened in two steps: First the magnetron was segmented into modular units. With this modularity in size, a exibility in target and substrate size arose. In addition, these individual segments were made twistable relative to each other. The eects on the performance of the magnetron with those changes were investigated. In a second step, the same existing cylindrical magnetron was modied again, this time to be suitable for supporting the coating process of inner surfaces of narrow tubes. This led to the main part of this thesis, namely the construction of a DC-magnetron sputtering device for coating inner surfaces of narrow tubes. In the following, the performance of this setup was tested with different target materials on conducting but also on insulating substrate-tubes. For the latter, a special supporting anode was designed. On both substrate types non-magnetic and even magnetic materials could be deposited in tubes with diameters as low as 8mm for insulating tubes.