Power Generation by Harvesting Ambient Energy with a Micro-Electromagnetic Generator

This thesis investigated the potential power output of micro-electromagnetic generators fabricated using typical microfabrication materials and techniques. The design was intended to eliminate the need for batteries in bio-implanted or remote electronic devices. Such a micro-generator could harvest ambient energy and power such devices indenitely. Using electromagnetic theory, designs for the magnets stator coil and rotor magnets were optimized to produce maximum current density. A method for overlaying two evaporated gold wires was devised and successfully fabricated in order to avoid side-wall thinning of the conductive coils. Once fabricated, the ferromagnetic nickel rotors were magnetized with an electromagnet. Testing of the magnets showed that the nickel rotors were able to be highly magnetized when placed near a strong eld, but, upon removal from the eld, the magnetization quickly dissipated. It was determined that the coercivity of electroplated nickel was too low for the rotor magnets to retain a eld for any appreciable amount of time. Testing of the micro-generator revealed that power output did not exceed 2 nA, thus nickel does not maintain the ux density required for such a generator and dierent materials should be investigated.