Abstract: The electronic device comprises a substrate (1) with a cavity (6) in which an active device (8) is present. On the first side (2) of the substrate an interconnect structure (17) extends over the cavity and the substrate. On the second side (3) of the substrate to which the cavity extends, a heat sink (23) is available. The device is particularly suitable for use at high frequencies, for instance higher than 2 GHz and under conditions of high dissipation.