&lt;title&gt;Comb drives: versatile microstructures for capacitive sensing and electrostatic actuation&lt;/title&gt;

Krijnen, Gijs; Kuijpers, A.A.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Elwenspoek, Michael Curt

doi:10.1117/12.508735

Cited by 3 publications

(3 citation statements)

References 22 publications

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“…This section makes comparison of the novel vertical comb-drive capacitor with the existing comb actuators. Comb drive based capacitors have been developed in [117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132]. The arrangement of the comb drives are either lateral or vertical [117,119].…”

Section: Comb Drive Actuatorsmentioning

confidence: 99%

Novel RF MEMS tunable capacitors

Hailu¹

2021

Preprint

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Current tunable devices such as filters, impedance matching networks and oscillators have problems that degrade their performance at high microwave frequencies. Tuning ratios and quality factors are the major problems associated with semiconductor based tuning components. This thesis presents the design, fabrication and testing of two novel RF MEMS tunable capacitors. The first tunable capacitor is designed using electrostatic repulsive-force actuators which produce an upward movement of the moving plate of a tunable capacitor. The repulsive-force actuator is free of pull-in effect and capable of reaching large displacement. Gap increasing tunable capacitors with areas of 162μm×220μm and 300μm×302μm are developed using electrostatic repulsive-force actuators. The capacitances are calculated using simulations and maximum tuning ratios of 438.5% and 230% are obtained for a parallel and inclined plate designs, respectively, with capacitance-voltage linearity of 96.28% and 95.14%, respectively, in the presence of RF voltage. The second tunable capacitor is developed using residual stress gradient based vertical comb-drive actuator. Conventional vertical comb-drive actuators need two vertical comb fingers, i.e., one for the fixed and one for the moving comb. MetalMUMPs process provides a 20μm thick nickel layer which is subject to residual stress gradient along its thickness. Using the residual stress gradient two curve-up beams are devised to bend out of plane and upward. A moving plate is connected between the middles of the curve-up beams through supporting springs and is raised above the substrate. The moving fingers are connected to opposite sides of the moving plate. The fixed comb-drive fingers are anchored to the substrate. When a voltage is applied, the moving fingers move down towards the fixed fingers. As a result, the capacitance between the moving fingers and the fixed fingers change. Prototypes are fabricated to verify the working principles of this novel actuator using the MetalMUMPs process. Tunable capacitors based on this actuator are experimentally analyzed. Quality factors of 106.9-162.7 at 0.8GHz and 42.4-51.9 at 1.24GHz are obtained over actuation voltage of 0-100V. An optimal design of the tunable capacitors achieved a tuning ratio of 194.4% at 162.5V with linearity of 97.84%

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Section: Comb Drive Actuatorsmentioning

confidence: 99%

Novel RF MEMS tunable capacitors

Hailu¹

2021

Preprint

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“…Micro vertical comb-drive actuators have been widely used in Microelectromechanical system (MEMS) devices (Lee 2011;Krishnamoorthy et al 2003Krishnamoorthy et al , 2006Xie and Fedder 2002;Tsuboi et al 2002;Kim et al 2000;Krijnen et al 2003;Patterson et al 2002;Selvakumar and Najaf 2003;Tang et al 1992;Hah et al 2004a;Lee et al 2003). The fabrication of vertical comb-drive actuators requires two structural layers of different heights to create the moving and the fixed comb fingers (Tang et al 1992).…”

Section: Introductionmentioning

confidence: 99%

Hybrid micro electrostatic actuator

Hailu

Mrad

2015

Microsyst Technol

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“…Conventional vertical comb-drive actuators require two structural layers, i.e. one for the moving fingers and one for the fixed fingers [9][10][11][12][13]. A number of process steps are necessary to fabricate the two layers [14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

A novel vertical comb-drive electrostatic actuator using a one layer process

Hailu

Mrad

2014

J. Micromech. Microeng.

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This paper presents the design, fabrication and testing of a new residual stress gradient based vertical comb-drive actuator. Conventional vertical comb-drive actuators need two structural layers, i.e. one for the moving fingers and a second for the fixed fingers. A vertical comb-drive actuator based on a single structural layer micromachining process, using the residual stress gradient along the thickness of the nickel of the MetalMUMPs (Metal Multi-User MEMS process) fabrication process, is developed. The MetalMUMPs provides a 20 μm thick nickel film and is subject to residual stress gradients along its thickness. Two curve-up beams are devised to curve out of plane after release. The curve-up beams raise a plate with comb fingers above the substrate to form the moving fingers. The fixed comb fingers are connected to the substrate via anchors. When a voltage is applied across the moving and the fixed fingers, the moving fingers move down towards the fixed fingers. Experimental measurements on prototypes have verified the design principle. A vertical displacement of 4.81 µm at 150 V was measured.

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<title>Comb drives: versatile microstructures for capacitive sensing and electrostatic actuation</title>

Abstract: This paper gives an overview of applications of so called comb-drives: micro-structures consisting of interdigitated conductive fingers from which one part can move and which can be used both as actuator and sensor.

Cited by 3 publications

References 22 publications

Novel RF MEMS tunable capacitors

Novel RF MEMS tunable capacitors

Hybrid micro electrostatic actuator

A novel vertical comb-drive electrostatic actuator using a one layer process

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