High-Q silicon membranes have been fabricated as resonator elements for excitation by magnetic direct generation of acoustic waves. Operating in the thickness shear mode, these inexpensive sensor elements are remotely excited by a planar spiral coil, driven by a radio frequency current and a strong static magnetic field. Modelling and FEM simulation have been done to improve the understanding of the sensor principle. Strong resonances with Q-factors up to 105 could be excited and detected successfully. Mass loading of these resonators shows Sauerbrey-like frequency shifts similar to quartz crystal microbalance sensors. © 2006 IOP Publishing Ltd.