A
resonator micro-electronic inertial sensor, preferably a micro-electromechanical
system (MEMS) sensor (e.g. a gyro), for detecting linear accelerations and rotation rates in more than one axis comprises: a proof-
mass system (21.1, 21.4) flexibly suspended above a substrate for performing a rotational in-plane vibration about a central axis (24,) a drive
electrode system (D1, . . . D4) for driving the proof-
mass system (21.1, . . . 21.4) to perform said rotational in-plane vibration, and a sensing
electrode system (S1, S8) connected to the proof-
mass system (21.1, . . . 21.4) for detecting linear accelerations or rotation rates in more than one axis. Said proof-
mass system (21.1 21.4) has more than two proof-mass elements flexibly coupled (25.1a, 25.1b) to each other. Each proof-
mass element (21.1, 21.2) is directly and flexibly connected (23.1, 25.1a, 25.1b) to an anchor structure (22) on the substrate (32). The proof-mass elements (21.1, . . . 21.4) are preferably arranged In a ring-shaped configuration between an inner and an outer
radius (R1, R2) with respect to the central axis (24).