Study Of Characteristic Of Nanomechanical Mixer

Nanoelectromechnical system, or NEMS, are MEMS scaled to submicron dimensions. In this size regime, there are different physical properties between NEMS and MEMS. In my paper, I introduce a theoretical modal to describe the behavior of NEMS device. Nanomechnical resonator is an important cell in NEMS, to study its nonlinear dynamics and its damping properties rich the theory of NEMS.Nonlinearity has another description in nanomechanical resonator, which drived by Lorentz force. we used external source sweep the frequency,if the frequency is increased, the displacement of beam under magnetic field is increased, after passing a max displacement, the beam tend to stop quickly, the driving frequency corresponding to max displacement exceeds the mechanical eigenfrequency of the resonator in linear range, this phenomena is called jump. The paper presents a theoretical model, based on the duffing equation, compute and analyze special beam with fixed length, width and height, the output show the theoretical model can accurately describe the behavior of the mechanical resonator. In the following, the paper discuss the mechanical mixing under two separate frequency sources, based on vibration theory of multi-excitation, nonlinear equation not only contains products of excitation frequency,but also produces a lot of harmonics in nonlinear range; the paper use numerical method to solve nonlinear equation, and show a multitude of satellite peaks evolves with the field strength increasing.Though the model describe the nonlinearity and mixing of the mechanical resonator, the parameters of model are obtained under the experiment, it is impossible to design the NEMS apparatus with the data given by experiment, so we must ensure all kinds of NEMS parameters in theory.For all these pursuits it is desired to design and construct systems with little loss of energy or very high quality factors Q, so damping coefficient is important in theoretical model. The paper discuss several kinds of energy dissipation mechanism, and make sure thermoelastic damping(THD) is fundamental dissipation mechanism. We simulate in normal temperature and conclude relation between damping coefficient and geometrical parameter of apparatus.The last, Making use of theory of THD analyze and solve the quality of THD of composite beam, show the relation between quality of THD of composite beam and thickness of Au layer of composite beam. This analyzing method can be taken as a reference for the design of the nanomechanical mixer.The paper have definite reference value for the design of the nanomechanical mixer farther.