Amplitude Ratio Shift Research Articles

A Micromechanical Mode-Localized Voltmeter

This paper reports a high-resolution voltmeter based on applying mode localization in a 3 DOF (degree of freedom) weakly coupled resonators (WCRs) system. When the input voltage is applied to the input electrode, stiffness perturbations are introduced into the two outer resonators, leading to a drastic change in mode shape owing to the mode localization phenomenon. Therefore, the input voltage can be detected by measuring the amplitude ratio shift of the WCRs. The theoretical model of the sensitivity is established and the detailed performances of the voltmeter are also given. The measured relative shift of amplitude ratio (~12549112 ppm/V) is 2918 times higher than that of the voltmeter is 3 μV/√(Hz) under the closed-loop test and errors resonant frequency (~4295 ppm/V). The noise floor of the of repeatability and backhaul are both less than 3%.

Weakly Coupled Piezoelectric MEMS Resonators for Aerosol Sensing.

This paper successfully demonstrates the potential of weakly coupled piezoelectric MEMS (Micro-Electro-Mechanical Systems) gravimetric sensors for the detection of ultra-fine particulates. As a proof-of-principle, the detection of diesel soot particles of 100 nanometres or less is demonstrated. A practical monitoring context also exists for diesel soot particles originating from combustion engines, as they are of serious health concern. The MEMS sensors employed in this work operate on the principle of vibration mode-localisation employing an amplitude ratio shift output metric for readout. Notably, gains are observed while comparing parametric sensitivities and the input referred stability for amplitude ratio and resonant frequency variations, demonstrating that the amplitude ratio output metric is particularly suitable for long-term measurements. The soot particle mass directly estimated using coupled MEMS resonators can be correlated to the mass, indirectly estimated using the condensation particle counter used as the reference instrument.

Dual Amplitude Shift Keying With Double Half-Wave Rectifier for SWIPT

We propose a receiver architecture and two modulation schemes for simultaneous wireless information and power transfer (SWIPT), in which two differently rectified signals are used for information decoding (ID) and energy harvesting (EH). The first scheme is called amplitude difference shift keying (ADSK), which gives a low bit error rate (BER) by transferring information through the amplitude difference between the two rectified signals. The second is called amplitude ratio shift keying (ARSK), which offers considerable harvested energy by transferring information through the amplitude ratio between the two rectified signals. We demonstrate how they work and provide their performance through simulations.

Design, modeling and theoretical analysis of a novel dual-axis hair flow sensor based on mode localization of weakly coupled resonators

This paper presents the design, modeling and theoretical analysis of a novel dual-axis hair flow sensor (DHFS) based on the mode localization of weakly coupled resonators (WCRs). A stereoscopic hair post is adopted to interact with external fluid and transmit the air flow velocity signal. Two-stage micro-leverage mechanisms are designed and optimized to amplify the drag force derived from external air flow. As the main sensitive elements, four optimized WCRs are symmetrically distributed around the main frame. A simplified theoretical model of DHFS is established and verified by comprehensive finite element method (FEM) simulations. Unlike the traditional frequency detection method, the presented DHFS detects the air flow velocity by measuring the amplitude ratio shift of two degree of freedom WCRs. The input-output response simulations demonstrate that the presented DHFS exhibits an x-axis sensitivity of 6.5026×10-2/(m/s)2 and a y-axis sensitivity of 6.4527×10-2/(m/s)2. In addition, the simulated relative shift in amplitude ratio (∼65000 ppm/(m/s)2) is three orders of magnitude larger than that in resonance frequency (∼50 ppm/(m/s)2). Meanwhile, the cross-axis sensitivities are 6.4387×10-4/(m/s)2 (x-axis) and 6.4475×10-4/(m/s)2 (y-axis), respectively. In summary, the feasibility of proposed structure architecture and operation principle is verified.

Highly sensitive resonant pressure sensor based on mode‐localisation effect

A novel micro-silicon resonant pressure sensor with two mechanically coupled resonators is presented. When pressure acts on the diaphragm, the perturbed stress will cause stiffness perturbation, leading to mode-localisation phenomenon. Therefore, pressure can be sensed by measuring the amplitude ratio shift. This novel structure is achieved by fabrication on silicon-on-insulator wafer. The measured result shows that the relative amplitude ratio shift (86,819.9 ppm/kPA) is 197.5 times higher than the shift in resonance frequency (439.6 ppm/kPA).

An Acceleration Sensing Method Based on the Mode Localization of Weakly Coupled Resonators

This paper reports an acceleration sensing method based on two weakly coupled resonators (WCRs) using the phenomenon of mode localization. When acceleration acts on the proof masses, differential electrostatic stiffness perturbations will be applied to the WCRs, leading to mode localization, and thus, mode shape changes. Therefore, acceleration can be sensed by measuring the amplitude ratio shift. The proposed mode localization with the differential perturbation method leads to a sensitivity enhancement of a factor of 2 than the common single perturbation method. The theoretical model of the sensitivity, bandwidth, and linearity of the accelerometer is established and verified. The measured relative shift in amplitude ratio ( $\sim 312162$ ppm/g) is 302 times higher than the shift in resonance frequency ( $\sim 1035$ ppm/g) within the measurement range of ±1 g. The measured resolution based on the amplitude ratio is 0.619 mg and the nonlinearity is $\sim 3.5$ % in the open-loop measurement operation. [2015-0247]