Linearity analysis of closed-loop capacitive accelerometer due to distance mismatch between plates and the influence of compensation capacitor array

Abstract

This paper presents mathematical formulae showing that the distance mismatch for an uncentered proof mass in an accelerator sensor does not influence the linearity of the closed-loop accelerometer as a whole. This asymmetry in sensors only introduces an output voltage offset in the readout integrated circuit. Numerical simulation using Matlab/Simulink confirms the mathematical conclusion. The linear response after compensation with a conventional capacitor array is also simulated and analyzed. Results show that there is a loss in linearity. Similar results hold not only for the continuous-time architecture, but also for a time-divided architecture. A readout integrated circuit with a time-divided architecture is designed and fabricated using a 0.35 µm HV CMOS process. An accelerometer composed of a microelectromechanical system sensor with severe built-in distance mismatch and the designed readout integrated circuit is tested. Test results show that the nonlinearity of such accelerometer is within 0.3%.

Broadband Plasmon‐Induced Transparency to a Electromagnetically Induced Absorption Conversion Metastructure Based on Germanium

“…To systematically study the formation mechanism of broadband EIA, the metastructure forming narrowband EIA is seen as a monolithic Part I, while the two metastructures used to increase the bandwidth, CRP and CRFS, can be made as a monolithic Part II [ 51 ] (see Figure 11d). Since the said Part I and Part II work in the EIA state when Ge is in the metallic state, the transmission coefficient is negligibly small and the conventional two‐port network can be regarded as a single‐port network.…”

Research on Decomposition of Offset in MEMS Capacitive Accelerometer

“…Because the reduction isn’t from mechanism, the performance of the offset, such as drift, cannot been improved. On the other hand, there have been many studies related to the source of the offset, such as material properties [ 7 ], gap mismatch [ 8 ], residual stress [ 9 ], and sensing circuit [ 10 ], but these papers have not analyzed the offset quantitatively. Moreover, some researchers have proposed methods of reducing the offset from a mechanism, such as optimizing the adhesive process [ 11 , 12 ], introducing a binary-weighted micro-capacitor [ 13 ], compensating based on the resonance frequency [ 14 ], improving the control system [ 15 ], and interface circuit technology [ 16 , 17 , 18 ].…”