A flexible membrane adapted to carry high-frequency power signals is described having a plurality of contact pads in a central portion of the flexible membrane connected to a plurality of micro contact probes and a plurality of contact structures connected to a support plate in a peripheral portion of the flexible membrane, as well as a plurality of conductive tracks connecting the contact pads with the contact structures. The flexible membrane further includes an intermediate portion between the central and peripheral portions. The elastic membrane is divided into a first area having a first total thickness and into a second area having a second total thickness. The first area is contiguous and adjacent to the second area. The first total thickness is less than or equal to 75 μm and the second total thickness is greater than the first total thickness.