Wideband MEMS resonator using multifrequency excitation

Abstract

The motivation of this study is to demonstrate the ability to excite the combination resonances near the first and third mode of vibration of clamped-clamped microbeams fabricated using surface micromachining techniques.  The ability to control the resonator bandwidth and the amplitude of vibration is demonstrated experimentally, by controlling the amplitude and frequency of the electrical excitation force.  This ability to excite multiple peaks and to control the resonator's bandwidth has promising applications in mass sensing and energy harvesting applications.  Another objective is to explore the dynamics of out-of-plane structures made of Polyimide, which is bio-compatible material. The surface of these microbeams can be functionalized with polymers and other sorbent materials to allow mass/gas detection. The information about the use of such material is scarce and is not available for the science community.  The final objective of this work is to study in details, the frequency response of these devices at the higher-order modes up to the nonlinear regime. Our study has shown interesting jumps and hardening effects at the higher-order modes.

A Coupled Resonator for Highly Tunable and Amplified Mixer/Filter

“…We notice that for every new mixedfrequency, two combination resonances are activated [26][27][28]. As the number of mixed frequencies is increased, the bandwidth increases.…”

“…To achieve mixing and to realize an amplified response at certain band of frequency, we exploit the quadratic electrostatic force and excite the H resonator with two or more excitation sources. This triggers the so-called combination resonances [26][27][28]. In the case of two AC harmonic sources in addition to the DC load, the electrostatic excitation load can be expanded as   …”

“…It is important to note here that the value and the associated V AC of the mixing frequency sources directly impact the flatness and bandwidth of the filter. The AC voltages associated with the mixing frequencies control the amplitude of the activated combination resonances while the values of mixing frequencies set the frequency of excitation of combination resonances [26][27][28]. The fixed frequency values and associated AC voltages are best chosen in such a way that the combination resonances are excited right next to each other with almost equal amplitudes.…”

“…Since the resonator always vibrates with the resonance frequency at these combination resonances, we utilize this property of the mixed-frequency excitation for frequency conversion [26][27][28]. Fig.…”

“…By exploiting the dynamic response of this coupled structure, maximum signal amplification (mechanical transformation) is achieved. Furthermore, we excite the structure using mixed-frequency electrostatic forcing [26][27][28] to achieve a wide relatively flat and amplified pass-band filtering and simultaneous mixing characteristics using a single resonator body. Fig.…”