Bandpass Analysis And Robust Structure Design For MEMS Resonators/Filters

With the fast development of telecommunication and electrical technology, the minimization of telecommunication system would be a trend. Micro-manufacture technology utilizes the standard integrated circuit process and adds the mechanical filter to the silicon chip, to buildup a single chip system, therefore, the whole volume of this system would be cut off. Just because of the bright promising of the micro-electromechanical filter, multiple structural modes of micro-electromechanical resonator/filter would be a hot project internationally.At present, the theoretical and experimental behavior of single vibration freedom micro-electromechanical filter/resonator have been studied perfectly, but single freedom filter has limited bandpass width, and the shape of bandpass, that is shape factor, which are not perfect and couldn't satify many situations. Multi-freedom micro-electromechanical filter/resonator, viewed as potential elements of high-Q electromechanical bandpass filters, has more potential on bandpass width and shape factor. Multi-freedom micro-eletromechanical filter/resonator could be designed by analog-filter's classic design theory. The core of theory is trial-numeration. However, the vibration model and analytic value of multi-freedom micro-electromechanical filter/resonator have not been worked out. Trial-numeration requires more trial calculations about the core parameters of filter, such as 3d Bbandpass width cut-off frequency and robust design to control fabrication variations of MEMS resonator.This paper treats micro-electromechanical comb resonators/filters and takes up with promoting and perfecting the design theory and method of micro-mechanical resonator and fitler.In this paper, main task and contributions as following two aspects: one is"The bandpass analysis of two vibration freedom micro-electromechanical bandpass filter", the other is"Robust Design to Control Fabrication Variations of MEMS Resonator".The content is as follows:Firstly, this paper dicussed the vibration model and analytic value of two-freedom micro-electromechanical resonator/filter, then a new method of filter design is discussed: to evaluate 3d Bbandpass width cut-off frequency. 3d BBandpass width cut-off frequency is near the natural frequency, it is reasonable to expand transmission function of the two vibration freedom micro-electromechanical bandpass filter on two natural frequencies respectively by Talor formula. However, considering the first derivative of transmission on the natural equals to zero, in this paper, the author expands Taylor formula to second order, and takes the definition of 3d Bbandpass width, deduces the 3d Bbandpass width calculating formula.Secondly, a new headway is made to minimize the fabrication error in two-freedom serial resonating system according to structure robust design method. The frequency characteristics of laterally vibrating resonator are analyzed. The fabrication tolerance not only changed the spring constant of resonator but also influence the practical mass, a variance even could bring different frequency variety of resonator structures. With the fabrication tolerance on width of resonator's edge being considered, the first and second order frequency sensitivities to the fabrication error are derived. To analyze the fold beam of laterally vibrating resonator, and use robust theory to control the process variation of resonator, A relationship for single material structures among the proof mass area, perimeter and the beam width, is utilized to attain the relative parameters formulae to optimize the structure. Design examples are given for the two -freedom and single-material serial resonating structures.This paper researches micro-electromechanical components and develops the relative level, specially about the micro-electromechanical filter, simultaneously, strengthens the theory and technology of theminimization of telecommunication system. The relative research projects in this paper is founded by NSFC [National Science Foundation of China]"Vibration robust control of Silicon micromechanical resonator and filter in telecommunication"(50305002). The output would perfect the design theory and methods of micromechanical resonator and filter, contribute to micro-manufacture technology.