Development of a Linearly Tunable Modified Butterfly-Shape MEMS Capacitor

2008 ◽  
Author(s):  
Mohammad Shavezipur ◽  
Seyed Mohammad Hashemi ◽  
Amir Khajepour ◽  
Patricia Nieva
Keyword(s):  
Actuation Voltage ◽  
Insulator Layer ◽  
Plate Electrode ◽  
Electrostatically Actuated ◽  
Monolithically Integrated ◽  
Tunable Capacitors ◽  
Capacitance Voltage ◽  
Rf Devices ◽  
Fixed Electrode ◽  
Structural Layer

This paper presents a novel geometry and modified structural stiffness for electrostatically actuated MEMS tunable capacitors. The design is based on parallel-plate configuration and four triangular plates are put together to form a butterfly shape flexible moving electrode. Each triangle is suspended by three uneven supporting beams. The capacitor is also equipped with extra beams, called here the “middle beams”, located under the triangles’ corners (nodes). An analytical model is developed to solve the governing equations of a triangular-plate electrode with uneven sides and supporting beams, where the stiffness of the middle beams is gradually added to the system as actuation voltage increases. The numerical simulations reveal that each triangle can be individually tuned up to 150% and the capacitance-voltage (C-V) response is broken into small sections due to added middle beams. Using the model developed in this paper and by design optimization, a linear C-V response is obtained, where the tunability in linear region reaches 100%. The simplicity of the proposed design allows the device to be fabricated using a three-structural-layer process such as PolyMUMPs and could therefore be monolithically integrated with other RF devices and ICs. Moreover, adding additional insulator layer on top of the fixed electrode increases the tunability to over 200% displaying a smooth and low sensitive response.

A Novel Highly Tunable Butterfly-Type MEMS Capacitor

2007 ◽  
Author(s):  
Mohammad Shavezipur ◽  
Amir Khajepour ◽  
Seyed Mohammad Hashemi
Keyword(s):  
Electrostatic Force ◽  
Actuation Voltage ◽  
Tunable Capacitor ◽  
Tunable Capacitors ◽  
High Tunability ◽  
Structural Rigidity ◽  
Highly Sensitive ◽  
Capacitance Voltage ◽  
Nodal Displacements ◽  
Q Factors

MEMS parallel-plate tunable capacitors are widely used in different devices such as tunable filters and resonators because of their simple structures, high Q-factors and small sizes. However, these capacitors have low tuning range with nonlinear and highly sensitive capacitance-voltage (C-V) responses. In this paper the development of novel tunable capacitor designs exhibiting highly linear C-V responses, is presented. The designs use segmentation technique to produce lumped flexibility in capacitor’s structure. A numerical model is developed to simulate the behavior of the capacitor. When a actuation voltage is applied, the structural rigidity of the plate produces resistive force which balances the electrostatic force, causes nodal displacements and changes the capacitance. It is shown that by optimizing the shape of segments (from rectangular to trapezoidal) and adding flexible steps located under the segments, a low sensitive linear C-V response could be achieved, while maintaining high tunability. The results of numerical simulation for the capacitors designed for PolyMUMPs process demonstrate that by optimization of the segments shape and structural stiffness a combination of high tunability over 100% and highly linear C-V response is achievable.

Casimir and Van Der Waals Effects on Parametric Resonance of Bio-NEMS Circular Plate Resonators

2015 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Reynaldo Oyervides
Keyword(s):  
Frequency Response ◽  
Parametric Resonance ◽  
Elastic Plate ◽  
Electrostatic Force ◽  
Van Der Waals ◽  
Circular Plates ◽  
Electrostatically Actuated ◽  
Sensing Applications ◽  
Fixed Electrode ◽  
Electrode Plate

This paper deals with Casimir and van der Waals effects on the frequency response of parametric resonance of electrostatically actuated NEMS circular plates for bio-sensing applications. The bio-NEMS resonator consists of a clamped circular elastic plate over a fixed electrode plate. A soft AC voltage of frequency near natural frequency between the plates gives an electrostatic force that leads the elastic plate into vibration which leads to parametric resonance that can be used afterwards for biosensing purposes. Frequency response and the effects of Casimir, and van der Waals forces on the response are reported.

Parametric Resonance of Electrostatically Actuated MEMS Cantilever Resonators Using Method of Multiple Scales and Homotopy Perturbation Method

2017 ◽  
Author(s):  
Christopher Reyes ◽  
Dumitru I. Caruntu
Keyword(s):  
Perturbation Method ◽  
Parametric Resonance ◽  
Homotopy Perturbation Method ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Electrostatic Force ◽  
Plate Electrode ◽  
Electrostatically Actuated ◽  
Homotopy Perturbation ◽  
Ground Plate

This paper investigates the dynamics governing the behavior of electrostatically actuated MEMS cantilever resonators. The cantilever is held parallel to a ground plate (electrode) with an AC voltage between the plate and the electrode causing the electrostatic actuation (excitation). For the purposes of this paper this is soft excitation. The frequency of the excitation is near the natural frequency of the cantilever leading to what is known as parametric resonance. The electrostatic force in the problem investigated throughout the paper is nonlinear in nature and includes the fringe effect. Two methods are used in investigating this problem: the method of multiple scales (MMS) and the homotopy perturbation method (HPM). The two methods work well for small non-linearities and small amplitudes. The influence of voltage, fringe, damping, Casimir, and Van der Waals parameters will be investigated in this paper using MMS and HPM as a means of verifying the results obtained.

scholarly journals Design of a large-range rotary microgripper with freeform geometries using a genetic algorithm

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Chen Wang ◽  
Yuan Wang ◽  
Weidong Fang ◽  
Xiaoxiao Song ◽  
Aojie Quan ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Human Hair ◽  
Design Methodology ◽  
Large Range ◽  
Design Method ◽  
Actuation Voltage ◽  
Superior Performance ◽  
Mems Devices ◽  
Electrostatically Actuated ◽  
Fabrication Tolerances

AbstractThis paper describes a novel electrostatically actuated microgripper with freeform geometries designed by a genetic algorithm. This new semiautomated design methodology is capable of designing near-optimal MEMS devices that are robust to fabrication tolerances. The use of freeform geometries designed by a genetic algorithm significantly improves the performance of the microgripper. An experiment shows that the designed microgripper has a large displacement (91.5 μm) with a low actuation voltage (47.5 V), which agrees well with the theory. The microgripper has a large actuation displacement and can handle micro-objects with a size from 10 to 100 μm. A grasping experiment on human hair with a diameter of 77 μm was performed to prove the functionality of the gripper. The result confirmed the superior performance of the new design methodology enabling freeform geometries. This design method can also be extended to the design of many other MEMS devices.

Design and Optimization of a New Highly Linear Tunable MEMS Capacitor

2007 ◽  
Author(s):  
Mohammad Shavezipur ◽  
Amir Khajepour ◽  
Seyed Mohammad Hashemi
Keyword(s):  
Voltage Response ◽  
Design And Optimization ◽  
Tunable Capacitor ◽  
Nonlinear Springs ◽  
High Tunability ◽  
Voltage Curve ◽  
Capacitance Voltage ◽  
Ideal Curve ◽  
Structural Layer ◽  
The Ideal

In this paper, a novel linearly tunable MEMS capacitor with high tunability is introduced. The characteristic air gap-voltage curve for an ideally linear tunable capacitor is studied. This curve is considered as a target for new designs. A three-structural layer process is used to develop the capacitor. The actuation and sense gaps in the three-plate capacitor are selected in such a way that for a voltage interval (between zero and pull-in), the gap-voltage response for sense electrodes becomes similar to the ideal curve. The resulting capacitance-voltage response of the new design demonstrates a combination of high linearity and tunability up to 250%. For processes which have fixed layer thickness and the sense and actuation gaps cannot be optimized, the design is modified by adding nonlinear springs and asymmetric geometry. The results of numerical simulation for a capacitor designed for PolyMUMPs process verify the improvement of linearity and tunability.

Fabrication of Variable Capacitor by Thin Copper Film with Electroplating

2003 ◽  
Vol 17 (08n09) ◽  
pp. 2001-2004 ◽  
Author(s):  
Chang Taeg Seo ◽  
Jae Ho Lee ◽  
Jong Hyun Lee ◽  
Young Ho Bae
Keyword(s):  
Tuning Range ◽  
Actuation Voltage ◽  
Copper Film ◽  
Error Rates ◽  
Micro Electro Mechanical Systems ◽  
Variable Capacitor ◽  
Tunable Capacitors ◽  
Copper Electroplating ◽  
Thin Copper Film ◽  
Electroplated Copper

The tunable capacitors have been fabricated by copper electroplating and MEMS(Micro-Electro-Mechanical Systems) technology. The thickness of electroplated copper which is used for moving electrode for variable capacitor below 0.5μm for lower actuation voltage. The fabricated tunable capacitors have been tested from 0V~42V and the resulting tuning range was between 62.3% and 90.2%. Also, the error rates have been presented ± 2.7% below.

The Design of Micro Electrostatic Structure with Low Driving Voltage

2013 ◽  
Vol 663 ◽  
pp. 560-565
Author(s):  
Zhi Xue Chen ◽  
Xu Han Dai ◽  
Qi Zhang ◽  
Wen Lu ◽  
Gui Fu Ding
Keyword(s):  
Actuation Voltage ◽  
Driving Voltage ◽  
Electrostatic Actuator ◽  
Fixed Electrode ◽  
Current Calculation

A new design of micro electrostatic actuator with low driving voltage is presented in this paper. It can reduce the operation voltage effectively without decreasing the gap between electrodes. In the proposed actuator with low driving voltage, the fixed electrode was designed as a stepped structure to divide the driving process into two steps. The peripheral electrode and inner electrode will be closed one by one. The two step pull-in processes will lower the actuation voltage significantly. According to the current calculation, the new structure with low driving voltage can reduce the actuate voltage significantly.

Pull-In Dynamics of Variable-Width Electrostatic Microactuators

2008 ◽  
Author(s):  
Manish M. Joglekar ◽  
Dnyanesh N. Pawaskar
Keyword(s):  
Constant Width ◽  
Actuation Voltage ◽  
Design Practice ◽  
Critical Amplitude ◽  
Electrostatically Actuated ◽  
Beam Geometry ◽  
Cantilevered Beam ◽  
Convex Geometries ◽  
Fixed Beam

Determination of pull-in parameters is vital in the design of electrostatically actuated microdevices. Moreover, it is important to devise some means to gain a control over the pull-in parameters in order to establish the customized microactuator design practice. In this paper, we analyze the influence of the beam geometry on the dynamic pull-in parameters of electrostatically actuated microbeams. Novel width functions are proposed for the microcantilever and the fixed-fixed beam, which smoothly vary the width of the microbeam along its length. We demonstrate the use of these width-functions by comparing six different microbeam geometries, three for cantilevered beam and three for fixed-fixed beam along with their constant width rectangular counterparts. All configurations are analyzed using an energy technique which gives an upper bound on the critical amplitude of the microbeam displacement, which is subsequently used to extract a lower bound on the applied voltage at the point of dynamic pull-in instability. For every case, a comparison is made between the static and the dynamic pull-in parameters. Results indicate a greater pull-in range for concave beam geometries, while the convex geometries exhibit a reduction in the pull-in range. Actuation voltage requirement is found to be proportional to the increase in the travel range. In all cases, the dynamic pull-in displacement is found to be greater than the static pull-in displacement, while the dynamic pull-in voltage is found to be less than the static pull-in voltage.

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