In this paper a new structure of electrostatically actuated clamped-clamped micro beam resonator is designed, modeled and simulated using aluminum as structural material to measure static to low frequency magnetic fields. The device is designed and simulated using CoventorWare simulation software to get mechanical properties using a static and dynamic displacement analysis and to get the optimum values of the beams parameters. The design is based on CMOS technology and surface micromachining. The resonant frequency increases with decreasing length, width and thickness of the micro beam resonator while the quality factor does not change with the change in the dimension of the resonator.