Flip-chip distributed MEMS transmission lines (DMTLs) for biosensing applications

Design and characterization of a flip-chip distributed MEMS transmission line (DMTL) are presented. The concept of using this DMTL as a biosensor is then introduced. Radio frequency experiments on the DMTL loaded with biosamples have been conducted using the most accessible materials, namely, deionized water and aqueous solutions of salts. Results show that the reflection coefficient (S11) of the solution-loaded DMTL is very sensitive to the salt concentration of the solution in the low-frequency ranges of 10 MHz-1 GHz and 3-4.5 GHz. At high frequencies, the relative dielectric constant of the biosample can also be quantitatively determined from the impedance of the DMTL

Analysis of microsprings for calculating the force produced by microactuators

We present models of two types of microsprings namely box-spring and zig-zag spring that can be used to measure the force generated by microactuators. The spring constant for both springs is calculated by FEM using ANSYS software. In these models, the effects of short beams that act as connectors in the spring structures are considered and analyzed by changing their width. Also, from the results, we find that the box spring appears more balanced than the zig-zag spring when the force is applied in the single central direction. A series of SDAs with box spring have been fabricated and forces ofthose SDAs have been calculated

Nonlinear dynamics of a doubly clamped carbon nanotube resonator considering surface stress

Doubly clamped carbon nanotube (CNT) resonators have received much attention due to their large stiffness, low density and small cross-section, making them suitable as highly sensitive mass sensors and signal processing units. In this paper, a new study on the dynamic performance of such resonators taking account of the surface effect has been performed and interesting findings have been unveiled. It is found that the surface effect causes increased resonant frequency, with the whirling and chaotic motions appearing at much higher driving forces. For the first time, the whirling motions for the centre point of the resonator in the Y–Z plane are found to display various Lissajous loops under different driving conditions. Based on the nonlinear analysis, a new application of the resonator for accelerometers has been postulated and analyzed

Simulation of Mass Sensor Based on Luminescence of Micro/Nano Electromechanical Resonator

We report a novel mass sensor based on detecting the luminescence from micro/nano electromechanical resonators. Multi-physics simulation has been conducted to elucidate this concept. It is found that the added mass affects both the resonant frequency and oscillating amplitude of the mechanical resonator. However we mainly use the change of oscillating amplitude to detect the added mass by observing varied optical intensity. For the device simulated, the sensitivity ((f=f0)=m per microgram) is 2% g1 if using frequency measurement through electronic circuits, while the sensitivity ((IL=I0)=m per microgram) is 377% g1 using amplitude measurement through the proposed optical method

Chaos control of parametric driven Duffing oscillators

Duffing resonators are typical dynamic systems, which can exhibit chaotic oscillations, subject to certain driving conditions. Chaotic oscillations of resonating systems with negative and positive spring constants are identified to investigate in this paper. Parametric driver imposed on these two systems affects nonlinear behaviours, which has been theoretically analyzed with regard to variation of driving parameters (frequency, amplitude). Systematic calculations have been performed for these two systems driven by parametric pumps to unveil the controllability of chaos

Optical driven electromechanical transistor based on tunneling effect

A new electromechanical transistor based on an optical driven vibrational ring structure has been postulated. In the device, optical power excites the ring structure to vibrate, which acts as the shuttle transporting electrons from one electrode to the other forming the transistor. The electrical current of the transistor is adjusted by the optical power. Coupled opto-electro-mechanical simulation has been performed. It is shown from the dynamic analysis that the stable working range of the transistor is much wider than that of the optical wave inside the cavity, i.e., the optical resonance enters nonperiodic states while the mechanical vibration of the ring is still periodic

Strain magnitude and direction effect on the energy band structure of hexagonal and orthorhombic monolayer MoS2

We report changes of the band structure of hexagonal and orthorhombic cells of the monolayer molybdenum disulfide (MoS2) subject to various magnitude and direction of the mechanical strains based on the first principle method. The conduction band minimum (CBM) of this two-dimensional (2D) material has been calculated to establish the relation with both the magnitude and direction of the strains. It is found that the CBM at Γ point of the hexagonal cell decreases in a slight concave shape for the tensile strain, and a convex shape for the compressive strain. For the orthorhombic cell, we demonstrate that the effect is almost independent on the direction of the applied tensile strain. However, there is a strong directional dependence for compressive strain