Increase of Three-Axis Accelerometer Sensitivity Using Capacitor in Spring

Document Type : Research Article


Faculty of Electrical and Computer Engineering, Babol Noshirvani University of Technology, Babol, Iran


This study has introduced a three-axis capacitive accelerometer, in which the part of the capacitor that calculates acceleration is installed in the z direction in the spring to improve the sensitivity in the said direction. In addition to having the advantages of previous accelerometers, the suggested accelerometer has compensated for previous shortcomings by increasing both sensitivity and pull-in voltage. Moreover, this accelerometer is able to decrease spring torsion and spring nonlinear behavior and provide a more straightforward rigidity computation. Therefore, without increasing the total occupancy level of the sensor, this accelerometer can increase the capacitive planes’ surface area to measure acceleration in z direction, resulting in an increase in sensitivity, while all the advantages of previous accelerometers are kept. In designing this accelerometer, factors such as rise time, overshoot, settling time, and peak time were considered. The proposed properties of the accelerometer were also derived from the perspective of a second-order system. Our designed accelerometer showed an operating frequency up to 20 kHz and a dynamic range up to 1000 g. The sensitivity of the accelerometer was 4fF/g in the z axis direction. Moreover, the sensitivity of the accelerometer in x and y directions was 9fF/g.


Main Subjects

[1] S. Luczak, W. Oleksiuk, M. Bodnicki, “Sensing tilt with MEMS accelerometers”, IEEE Sens. J., vol. 6, pp. 1669–1675, 2006.
[2] R. Perez, Ú. Costa, M. Torrent, J. Solana, E. Opisso, C. Caceres, J.M. Tormos, J. Medina, E.J. Gómez, “Upper Limb Portable Motion Analysis System Based on Inertial Technology for Neurorehabilitation Purposes”,Sensors, vol.10, pp. 10733–10751, 2010.
[3] A. Aydemira, T. Akina, “Process Development for the Fabrication of a Three Axes Capacitive MEMS Accelerometer, Procedia Engineering”, Elsevier Journal, pp. 727 – 730, 2015.
[4] G.-S. Lee, S.-H. Ahn, S.-D. Shon, and S.-J. Lee, “A study on the accelerometer for the acceleration and inclination estimation of structures using double-FBG optical sensors”, J. Korean Assoc. Spatial Struct., vol. 16, no. 1, pp. 85_94, Mar. 2016.
[5] A. Aydemir, Y. Terzioglu, and T. Akin, “A new design and a fabrication approach to realize a high performance three axes capacitive MEMS accelerometer”, Sens. Actuators A, Phys., vol. 244, pp. 324_333, Jun. 2016.
[6] V. Benevicius, V. Ostasevicius, and R. Gaidys, “Identification of Capacitive MEMS Accelerometer Structure Parameters for Human Body Dynamics Measurements”, Sensors Journal, pp. 11184-11195, 2013.
[7] S. Tez, U. Aykutlu, M. M. Torunbalci, and T. Akin, “A Bulk-Micromachined Three-Axis Capacitive MEMS Accelerometer on a Single Die”, In IEEE Journal of Microelectromechanical Systems, pp. 1264-1274, 2015.
[8] K. Delfan Hemmati, B. Azizollah Ganji, “A new structure and modeling of a three-axis MEMS capacitive accelerometer with high dynamic range and sensitivity”, journal of Microsystem Technologies, 2020.
[9] H. Hamaguchi,  K. Sugano,  T. Tsuchiya, and O. Tabata, “A Differential Capacitive Three Axis Soi Accelerometer Using Vertical Comb Electrodes”,   In IEEE International Solid-State Sensors, Actuators and Microsystems Conference, 2007, pp. 1483-1486.
[10] B. Bais, and B. Y. Majlis, “Structure Design and Fabrication of an Area changed Bulk Micromachined Capacitive Accelerometer”, In IEEE International Conference on Semiconductor Electronics, 2006, pp. 29-34.
[11] J. Chae, H. Kulah, and K. Najafi, “A Monolithic Three-Axis Micro-g Micromachined Silicon Capacitive Accelerometer”, Journal of Microelectromechanic Systems, pp. 235-241, 2005.
[12] I. Zeimpekis, and M. Kraft, “Single Stage Deflection Amplification Mechanism in a SOG Capacitive Accelerometer”, Journal of Procedia Chemistry, pp. 883-886, 2009.
[13] K. H. L.Chau, S. R. Lewis, y. Zhao, R. T. Howe, and S. F. Bart, R. G. Marcheselli, “An Integrated Force-Balanced Capacitive Accelerometer for Low-g Applications”,  In Proceedings of the International Solid-State Sensors and Actuators Conference, 1996, pp. 472-476.
[14]T.Tsuchiya, and H. Funabashi, “A Z-Axis Differential Capacitive SOI Accelerometer with Vertical Comb Electrodes”, In 17th IEEE International Conference on Micro Electro Mechanical Systems, 2004, pp. 378–383.
[15] P. Bruschi, A. Nannini, D. Paci, and F. Pieri, “A Method for Cross-Sensitivity and Pull-In Voltage Measurement of MEMS Two-Axis Accelerometers”, Sensors and Actuators A: Physical, Elsevier, pp. 185–193, 2005.
[16] H. Tavakoli, and E. A. Sani, “A New Method for Eliminating cross Axis Sensitivity in Two Axis Capacitive Micromachined Accelerometers”, In 21st Iranian Conference on Electrical Engineering (ICEE), 2013, pp. 595-598. 
[17] A. Aydemir, Y. Terzioglu, T. Akin, “A new design and a fabrication approach to realize a high performance three axes capacitive MEMS accelerometer”, Sensors and Actuators A: Physical, Elsevier, pp. 324-333.