Dynamic behaviours of the Double-end tuning fork based comb-driven microelectromechanical resonators for modulating the magnetic flux synchronously

Author(s):  
Zhenxi Liu ◽  
Jiamin Chen ◽  
Wuhao Yang ◽  
Tianyi Zheng ◽  
Qifeng Jiao ◽  
...  

Abstract MEMS resonators have been widely used in the magneto-resistive (MR) sensor for modulating the magnetic flux to enhance the detection limit. However, the manufacturing tolerances in MEMS fabrication processes make it challenging to fabricate the identical resonators with the same vibration frequency, which greatly decreases the detection limit of the MR sensor. To synchronize the MEMS resonators and improve the performance of the MR sensor, the double end tuning fork (DETF) based comb-driven MEMS resonators is proposed in this paper, making the system operate at the out-of-phase mode to complete the synchronization. The dynamic behaviour of the resonators is investigated through theoretical analysis, numerical solution based on MATLAB code and Simulink, and experimental verification. The results show that the transverse capacitances in the comb will significantly affect the resonance frequency due to the second-order electrostatic spring constant. It is the first time to observe the phenomenon that the resonant frequency increases with the increase of the bias, and it can also decrease with increasing the bias through adjusting the initial space between the fixed finger and the moving mass, they are different from the model about spring softening and spring hardening. Besides, the proposed DETF-based comb-driven resonators can suppress the in-phase and out-of-phase mode through adjusting the driving and sensing ports, and sensing method, meanwhile make the magnetic flux modulation fully synchronized, and maximize the modulation efficiency, and minimize the detection limit. These characteristics are appropriate for the MR sensor, even other devices that need to adjust the resonance frequency and vibration amplitude. Furthermore, the model and the design can also be extended to characteristic the single end tuning fork (SETF) based MEMS resonator and other MEMS-based MR sensors.

2016 ◽  
Vol 30 (30) ◽  
pp. 1650364 ◽  
Author(s):  
Zhouqiang Zhang ◽  
Shuhai Jia ◽  
Yonglin Wang ◽  
Zhenhua Tang ◽  
Fei Wang

In this paper, a transparent vacuum-encapsulated quartz tuning fork (QTF) is proposed for the first time to improve the quality factor and sensitivity of QTF sensors. Increasing the vacuum considerably improved the quality factor of QTF, and the resonance frequency was also shifted to higher values to 10 Hz. Subsequently, the spectroscopy detection of acetylene gas using an exposed QTF and a transparent vacuum-encapsulated QTF was investigated. The sensitivity of the detection system improved in the presence of the transparent vacuum-sealed QTF. The current findings represent a gateway to subsequent research in photo-thermoelastic spectroscopy.


2013 ◽  
Vol 562-565 ◽  
pp. 436-440
Author(s):  
Chao Wei Si ◽  
Guo Wei Han ◽  
Jin Ning ◽  
Wei Wei Zhong ◽  
Fu Hua Yang

A new kind of wind sensor made up of MEMS resonators is designed in the paper capable of sensing the lift, the resistance and the turbulence of airplane wings by mounting on the surface. The designed wind sensor is made up of four MEMS wind pressure gauges fixed around a square wind resistance block which used to block the wind to change the wind pressure on the surface, and the change of wind pressure is detected by MEMS wind pressure gauges to reveal the air condition on the surface of the airplane wings. As known, a MEMS resonator is a second-order resonant system whose damping factor is mainly dependent on the air pressure, and the characteristic is often used to detecting the airtightness of a sealed chamber for the damping factor is sensitive under high vacuum, while a MEMS resonator with the damping factor sensitive at atmospheric pressure is designed in this paper for sensing wind pressure change, and the MEMS resonator is manufactured on SOI substrates with deep reactive ion etching technology. Also relations between the wind pressure change and the wind speed around a block at atmosphere is revealed by finite element simulation. Compared to traditional wind sensors such as anemometers and Venturi tubes, the designed MEMS wind sensor with a very small size is suitable to mount on different zones of a wing with a large amount to monitor the air condition and have less influence on air flow.


2011 ◽  
Vol 1299 ◽  
Author(s):  
P. M. Sousa ◽  
V. Chu ◽  
J. P. Conde

ABSTRACTIn this work, we present a reliability and stability study of doped hydrogenated amorphous silicon (n+-a-Si:H) thin-film silicon MEMS resonators. The n+-a-Si:H structural material was deposited using radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) and processed using surface micromachining at a maximum deposition temperature of 110 ºC. n+-a-Si:H resonant bridges can withstand the industry standard of 1011 cycles at high load with no structural damage. Tests performed up to 3x1011 cycles showed a negligible level of degradation in Q during the entire cycling period which in addition shows the high stability of the resonator. In measurements both in vacuum and in air a resonance frequency shift which is proportional to the number of cycles is established. This shift is between 0.1 and 0.4%/1x1011 cycles depending on the applied VDC. When following the resonance frequency in vacuum during cyclic loading, desorption of air molecules from the resonator surface is responsible for an initial higher resonance frequency shift before the linear dependence is established.


Author(s):  
Dumitru I. Caruntu ◽  
Christian Reyes

This paper deals with the voltage-amplitude response (or voltage response) of superharmonic resonance of second order of MEMS resonator sensors under electrostatic actuation. The system consists of a MEMS flexible cantilever above a parallel ground plate. The AC frequency of actuation is near one fourth the natural frequency. The voltage response of the superharmonic resonance of second order of the structure is investigated using the Reduced Order Model (ROM) method. Effects of voltage and damping voltage response are reported.


2019 ◽  
Vol 7 (18) ◽  
pp. 5394-5400 ◽  
Author(s):  
A. C. Lima ◽  
N. Pereira ◽  
R. Policia ◽  
C. Ribeiro ◽  
V. Correia ◽  
...  

For the first time is reported the development of a screen printed flexible magnetoelectric material based on P(VDF–TrFE), PVDF and CoFe2O4. The ME voltage coefficient of 164 mV cm−1 Oe−1 at a longitudinal resonance frequency of 16.2 kHz, the highest reported in the literature, certifies the use of the printed material on printed electronics, sensors, actuators, and energy harvesters.


1994 ◽  
Vol 154 ◽  
pp. 493-497 ◽  
Author(s):  
Steven H. Saar

I present a preliminary analysis of IR spectra of five K and M dwarfs and two RS CVn variables. Evidence for significant magnetic flux is found on several stars, a number of which are detected for the first time. Field strengths (B) on the RS CVn variables are lower than in the active dwarfs, consistent with the concept of pressure balance limiting B in stellar photospheres. I compare the results with previous measurements.


Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2686
Author(s):  
Manhee Lee ◽  
Bongsu Kim ◽  
Sangmin An ◽  
Wonho Jhe

A quartz tuning fork and its qPlus configuration show different characteristics in their dynamic features, including peak amplitude, resonance frequency, and quality factor. Here, we present an electromechanical model that comprehensively describes the dynamic responses of an electrically driven tuning fork and its qPlus configuration. Based on the model, we theoretically derive and experimentally validate how the peak amplitude, resonance frequency, quality factor, and normalized capacitance are changed when transforming a tuning fork to its qPlus configuration. Furthermore, we introduce two experimentally measurable parameters that are intrinsic for a given tuning fork and not changed by the qPlus configuration. The present model and analysis allow quantitative prediction of the dynamic characteristics in tuning fork and qPlus, and thus could be useful to optimize the sensors’ performance.


The Analyst ◽  
2018 ◽  
Vol 143 (18) ◽  
pp. 4354-4358 ◽  
Author(s):  
Hai Xu ◽  
Zhen Huang ◽  
Yaqian Li ◽  
Biao Gu ◽  
Zile Zhou ◽  
...  

The ‘C–CN’ bond cleavage was applied to the recognition of N2H4 for the first time; the obvious change in color could be used for “naked-eye” detection; the corresponding detection limit was found to be 5.81 × 10−8 M (1.65 ppb); the probe could be applied for N2H4 detection in real water samples.


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