This paper presents the fabrication, modeling, and characterization of an in-plane approximated nonlinear MEMS electromagnetic energy harvester (EM-EH) device. The approximated nonlinearity and frequency broadening of the device are realized by incorporating small suspension structures, which introduces the spring hardening effect and thus increases the operating frequency of the device toward a higher frequency interval. From the experimental results, the resonant frequencies during frequency up-sweep have been shifted from the original resonance of 82 Hz to 123.5, 135, and 146.5 Hz, at the accelerations of 1.0, 2.0 and 3.0 g, respectively. The corresponding power densities at resonances are 1.6 x 10(-8), 2.8 x 10(-8), and 5.6 x 10(-8) W/cm(3). This paper offers a new design methodology of the approximated nonlinear MEMS EM-EH device. [2013-0080]