Microfluidic device and method of operation

A MEMS device for determining at least one property of a fluid, the device comprising:

• a substrate;
• a structure on the substrate, the structure comprising a base attached to the substrate and a tube attached to and extending from the base and spaced apart from a surface of the substrate so as to be capable of vibrational movement relative to the base and the substrate in a plane normal to the surface of the substrate, the tube comprising a continuous internal passage, a fluid inlet and a fluid outlet of the internal passage fluidically connected to the base, and a distal portion relative to the base, the vibrational movement of the tube comprising a twisting motion that applies mechanical stresses to an attachment between the tube and base resulting in clamping losses that are dissipated through the base to the substrate;
• a cantilevered member attached to the distal portion of the tube and configured for vibrational movement relative to the distal portion and in a plane normal to the surface of the substrate, wherein the vibrational movement of the cantilevered member counteracts the vibrational movement of the tube to minimize clamping losses dissipated to the substrate;
• at least one drive electrode on the surface of the substrate, adjacent at least one of the cantilevered member and the distal portion of the tube, and operable to induce the vibrational movements of the tube and the cantilevered member;
• sensing electrodes on the surface of the substrate, the sensing electrodes being adapted to sense deflections of the tube when vibrated with the drive electrode and produce outputs corresponding to the sensed deflections;
• and
• means for determining from the outputs of the sensing electrodes at least one property of a fluid flowing through the internal passage.