A micromechanical spectrum analyzer
Over the past two decades, progress in the development and deployment of radio-frequency wireless communication devices has created a need for improved system performance in signal processing systems, particularly with respect to component size, battery life, power consumption and cost. These stringent requirements have generated considerable interest in microelectromechanical systems (MEMS), due their distinct utility in practical applications, which stems from their small size, fast response, low power consumption, and near-seamless integrability with on-chip electronics. ^ The current work follows this trend by gainfully employing MEMS technology in the development of a chip-scale mechanical spectrum analyzer. Specifically, a microresonator array architecture, consisting of frequency mistuned microbeams that are elastically coupled through a common shuttle mass, has been developed. A form of vibration localization is exploited in this device, wherein the central shuttle mass, facilitates signal distribution, while each mistuned microbeam creates a frequency band that can be used in mechanical spectral decomposition. This novel approach offers one route to real-time spectral analysis with a simple, low-power, chip-scale device. The system is modeled and analyzed using a lumped parameter approach and then designed using the finite element method. A set of design guidelines is introduced to ensure the existence of mode localization in the device and the attainment of desired performance metrics. A recipe for a three step microfabrication procedure and possible directions for future work are also presented.^
Jeffrey Rhoads, Purdue University.