Finite element modeling and simulation of ultrasensitive film bulk acoustic resonator enabled by micropillar structure

2021 ◽  
pp. 2140007
Author(s):  
Jie Peng ◽  
Haoran Niu ◽  
Jinlin Liu ◽  
Ya-Nan Yang ◽  
Junze Zhu ◽  
...  
Keyword(s):  
Finite Element ◽  
Resonant Frequency ◽  
Frequency Shift ◽  
Acoustic Resonator ◽  
Optimized Design ◽  
Nonlinear Frequency ◽  
Mass Sensitivity ◽  
Resonant Frequency Shift ◽  
Film Bulk Acoustic Resonator ◽  
Film Bulk

Portable and ultra-sensitive film bulk acoustic resonator (FBAR) is a promising device to satisfy the requirement of detecting gas and biological molecule. In this work, a novel sensing device was developed to achieve ultrahigh sensitivity, by coupling polymer micropillars with a FBAR substrate to form a two-degrees-of-freedom resonance system (FBAR-micropillars). We systematically investigated the effects of micropillar structure on the characteristics of FBAR-micropillars device by finite element method (FEM). It was found that the resonant frequency shift increased with increasing the height of micropillars (h) within a certain range, and the FBAR-micropillars device displayed nonlinear frequency response, which was opposite to the linear response of conventional FBAR devices. In addition, a positive resonant frequency shift was captured near the “coupled resonant point” of the FBAR-micropillars device. The geometric parameters of micropillars, including micropillar diameter and micropillar spacing could also cause a change of Q-factor and mass sensitivity. The optimized design of the proposed device achieved a threefold improvement in sensitivity relative to conventional FBAR without pillars, suggesting a feasible method to improve the mass sensitivity of acoustic resonators.

MASS DETECTION USING SINGLE WALLED BORON NITRIDE NANOTUBE AS A NANOMECHANICAL RESONATOR

NANO ◽  
2012 ◽  
Vol 07 (04) ◽  
pp. 1250029 ◽  
Author(s):  
MITESH B. PANCHAL ◽  
S. H. UPADHYAY ◽  
S. P. HARSHA
Keyword(s):  
Boron Nitride ◽  
Resonant Frequency ◽  
Frequency Shift ◽  
Continuum Mechanics ◽  
Boron Nitride Nanotubes ◽  
Tube Length ◽  
Thin Wall ◽  
Nanomechanical Resonators ◽  
Mass Sensitivity ◽  
Resonant Frequency Shift

The feasibility of the Boron Nitride Nanotubes (BNNTs) as nanomechanical resonators, using continuum mechanics based approach and finite element method (FEM) is illustrated in this paper. Two types of end constraints of single walled boron nitride nanotubes (SWBNNTs), namely cantilevered and bridged are assumed. Analytical formulas based on continuum mechanics are used to examine the mass sensitivity of SWBNNTs considering as a thin wall tubes for both types of end constraints for different lengths and different diameters. The FEM analysis, considering SWBNNT as a transversely anisotropic material is performed and results are compared with the continuum mechanics based approach. The results indicated that the mass sensitivity of SWBNNT-based nanomechanical resonators can reach 10-8fg and a logarithmically linear relationship exists between the resonant frequency and the attached mass, when mass is larger than 10-7fg. The sensitivity of resonant frequency shift to both tube length and diameter has also been demonstrated. It is clear that the change in resonant frequency shift to tube length is more significant than that with the tube diameter and mass sensitivity increases when smaller size nanotube resonators are used in mass sensors. The simulation results based on present FEM found in good agreement with the analytical approach.

Doubly-Clamped Single Walled Boron Nitride Nanotube Based Nanomechanical Resonators: A Computational Investigation of Their Behavior

2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Mitesh B. Panchal ◽  
S. H. Upadhyay
Keyword(s):  
Finite Element ◽  
Boron Nitride ◽  
Resonant Frequency ◽  
Frequency Shift ◽  
Dynamic Behavior ◽  
Added Mass ◽  
Boron Nitride Nanotube ◽  
Landing Position ◽  
Nanomechanical Resonators ◽  
Resonant Frequency Shift

This paper illustrates the dynamic behavior of a doubly-clamped single walled boron nitride nanotube (SWBNNT) as a mass sensor. To this end, a 3-dimensional atomistic model based on molecular structural mechanics is developed such that the proximity of the model to the actual atomic structure of the nanotube is significantly retained. Different types of zigzag and armchair layouts of SWBNNTs are considered with doubly-clamped end constraints. Implementing the finite element simulation approach, the resonant frequency shift based analysis is performed for doubly-clamped end-constraints, for an additional nanoscale mass at the middle of the length, and at the intermediate landing position along the length of the nanotube. The effect of the intermediate landing position of added mass on the resonant frequency shift is analyzed by considering excitations of the fundamental modes of vibration. The finite element method (FEM) based simulation results are validated using the continuum mechanics based analytical results, considering the effective wall thickness of the SWBNNT. The present approach is found to be effectual in terms of dealing with different chiralities, boundary conditions, and the consideration of the added mass to analyze the dynamic behavior of the doubly-clamped SWBNNT based nanomechanical resonators.

Sensing characteristics of pure-shear film bulk acoustic resonator in viscous liquids

2017 ◽  
Vol 31 (08) ◽  
pp. 1750086 ◽  
Author(s):  
Da Chen ◽  
Shuren Song ◽  
Dexue Zhang ◽  
Peng Wang ◽  
Weihui Liu
Keyword(s):  
Pure Shear ◽  
Acoustic Resonator ◽  
Frequency Change ◽  
Glycerol Solution ◽  
Viscous Liquids ◽  
Mass Sensitivity ◽  
Aln Film ◽  
Film Bulk Acoustic Resonator ◽  
Film Bulk ◽  
Sensing Characteristics

We presented a pure-shear film bulk acoustic resonator (FBAR) and investigated its sensing characteristics in viscous liquids. In the resonator, the electrodes were located on the surface of c-axis-oriented AlN film to generate the lateral electric field and excite the shear acoustic resonance. Compared with the typical quasi-shear film bulk acoustic resonator based on inclined c-axis-oriented AlN or ZnO piezoelectric film, the proposed device exhibits significantly higher Q-factors and a notably improved detection limit, particularly in water and viscous liquids. The frequency shifts show a linear dependency on the square root of the product of the liquid viscosity and density of the glycerol solution in the viscosity range of 1–5 mPa[Formula: see text]s. Furthermore, we measured the mass sensitivity through real-time monitoring of the frequency change during the volatilization process of the loaded saline solutions. The proposed device shows the mass sensitivity of 465 Hz[Formula: see text]cm2/ng and the mass resolutions of 0.17 ng/cm2 in air, 0.25 ng/cm2 in water and 2.08 ng/cm2 in 50% glycerol solution, respectively. The obtained results clearly indicate that the proposed device is capable of using in liquid phase detection with high sensitivity requirements.

Sign in / Sign up

Export Citation Format

Share Document