Theory and experimental research for the double ended tuning fork in MEMS

Purpose - Being the key sensitive elements of the micro-electromechanical systems (MEMS) resonant sensors, performance of the double-ended tuning fork (DETF) will affect precision of the whole sensor greatly. Currently, most of the research on DETF is concentrated on ideal theory or simply mentioned as part of the sensor. But, in most engineering occasions, there exists many factors such as the additional mass, air damping and fabrication process, etc. However, few references are individually aimed at the mechanical characters of DETF. To choose the suitable DETF, it is important to solely research and measure the performance of this element. Design/methodology/approach - In this paper, the authors combine the practical engineering applications and deduce the calculation method of sensitive element's resonant frequency under various circumstances. The authors also design a force-generating system to make the loading simulation and verify the correctness of theory. Findings - On the basis of Euler-Bernoulli theory and Rayleigh's equation, frequency theories of DETF under four different situations have been deduced. A force-generating device is designed and fabricated to measure the mechanical characters of the DETF. The experiments using force-generating system, DETF, the high performance laser vibrometer and oscillograph are carried out. It verifies the correctness of theory. Originality/value - Currently, most of the research on DETF is concentrated on ideal theory or simply mentioned as part of the sensor, and few references are individually aimed at the mechanical characters of DETF. Combining the practical engineering applications, the authors deduced the frequency theories of DETF. A force-generating system is designed and fabricated to measure the mechanical characters of the DETF, and the experiment results match the theoretical results very well.