A new electrochemical angular microaccelerometer with integrated sensitive electrodes perpendicular to flow channels.

A new electrochemical angular microaccelerometer with integrated sensitive electrodes perpendicular to flow channels was developed in this paper. Based on a liquid inertial mass, an incoming angular acceleration was translated into varied concentrations of reactive ions around sensitive microelectrodes, generating a detection current. Key structural parameters of the sensitive microelectrodes were designed and compared based on theoretical analysis and numerical simulations. An angular microaccelerometer incorporating sensitive microelectrodes was then fabricated, assembled and characterized, producing a sensitivity of 338 V/(rad/s2), a -3 dB bandwidth of 0.01-10 Hz and a noise level of 4.67 × 10-8 (rad/s2)/Hz1/2 @ 1 Hz. These performances were better than their commercial counterparts based on traditional electrodes and previously reported microaccelerometers based on microsensitive electrodes in parallel with flow channels, which can be applied to measure rotational accelerations in earthquakes and buildings.

A MEMS Electrochemical Seismometer Based on the Integrated Structure of Centrosymmetric Four Electrodes.

This paper presented an electrochemical seismic micro sensor based on an integrated structure of four centrosymmetric electrodes. In this integrative structure, cathodes were not only distributed on wafer surfaces but also on the inner walls of the flow holes of the wafer, which increased the effective cathode areas and improved the sensitivity of the sensor. Numerical simulations were conducted to validate the feasibility of the integrated structure of four centrosymmetric electrodes in monitoring seismic vibrations where variations in the arrangements of the flow holes and anode width were investigated. The integrated structure of the four centrosymmetric micro electrodes was fabricated based on Micro-Electro-Mechanical Systems (MEMS) without the requirement of manual alignments. Experimental characterizations revealed that: (1) the maximum sensitivity of the electrochemical seismic sensor based on the integrated structure of four centrosymmetric electrodes was two orders of magnitude higher than that of the commercial counterpart of CME6011 and three times higher than the electrochemical seismic sensor based on the integrated structure of four planar micro electrodes; (2) the electrochemical seismic sensor based on the integrated structure of four centrosymmetric micro electrodes demonstrated comparable and even lower noise levels in comparison to CME6011. Thus, the electrochemical seismic micro sensor developed in this study may function as an enabling tool in future applications of seismic monitoring and geophysical explorations.

A MEMS Electrochemical Angular Accelerometer Leveraging Silicon-Based Three-Electrode Structure.

This paper developed an electrochemical angular micro-accelerometer using a silicon-based three-electrode structure as a sensitive unit. Angular acceleration was translated to ion changes around sensitive microelectrodes, and the adoption of the silicon-based three-electrode structure increased the electrode area and the sensitivity of the device. Finite element simulation was conducted for geometry optimization where the anode length, the orifice diameter, and the orifice spacing of the sensitive unit were determined as 200 µm, 80 µm, and 500 µm, respectively. Microfabrication was conducted to manufacture the silicon-based three-electrode structure, which then was assembled to form the electrochemical angular micro-accelerometer, leveraging mechanical compression. Device characterization was conducted, where the sensitivity, bandwidth, and noise level were quantified as 290.193 V/(rad/s2) at 1 Hz, 0.01-2 Hz, and 1.78 × 10-8 (rad/s2)/Hz1/2 at 1 Hz, respectively. Due to the inclusion of the silicon-based three-electrode structure, compared with previously reported electrochemical angular accelerometers, the angular accelerometer developed in this article was featured with a higher sensitivity and a lower self-noise level. Therefore, it could be used for the measurement of low-frequency seismic rotation signals and played a role in the seismic design of building structures.

A MEMS-Based Co-Oscillating Electrochemical Vector Hydrophone.

Aiming at the development needs of low-frequency and high-sensitivity vector hydrophones, this paper has developed a micro-electro-mechanical system (MEMS) based co-oscillating electrochemical vector hydrophone. We obtained the optimized geometric parameters through simulation analysis of the diameter of the rubber membrane, the length of the flow channel and the diameter of the flow holes. Based on the simulation results, electrodes were fabricated using MEMS technology, and were then assembled and tested. Device characterization was conducted, where the sensitivity and bandwidth were quantified as 0.5-150 Hz, -187 dB ref. 1 V/µPa, respectively. Compared with a previously reported co-oscillating vector hydrophone, the co-oscillating vector hydrophone developed in this article featured a lower working frequency band.