DESIGN, SIMULATION AND BIFURCATION ANALYSIS OF A NOVEL MICROMACHINED TUNABLE CAPACITOR WITH EXTENDED TUNABILITY

2014 ◽  
Vol 38 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Hamed Mobki ◽  
Kaveh Rashvand ◽  
Saeid Afrang ◽  
Morteza H. Sadeghi ◽  
Ghader Rezazadeh
Keyword(s):  
Cantilever Beam ◽  
Rf Mems ◽  
Reference Electrode ◽  
Lower Plate ◽  
Equivalent Stiffness ◽  
Unstable Condition ◽  
Tunable Capacitor ◽  
Movable Electrode ◽  
Micro Structures ◽  
Bifurcation Behavior

In this paper, a novel RF MEMS variable capacitor has been presented. The applied techniques for increasing the tunability of the capacitor are the increasing of the maximum capacitance and decreasing of the minimum capacitance. The proposed structure is a simple cantilever Euler–Bernoulli micro-beam suspended between two conductive plates, in which the lower plate is considered as stationary reference electrode. In this structure, two pedestals are located in both tips of the cantilever beam. In the capacitive micro-structures, increasing the applied voltage decreases the equivalent stiffness of the structure and leads the system to an unstable condition (pull-in phenomenon). By deflecting the beam toward the upper (lower) plate the minimum (maximum) capacitance decreases (increases) and tunability increases consequently. The located pedestals increase and decrease the maximum and minimum capacitance respectively. The results show that the proposed structure increases the tunability of cantilever beam significantly. Furthermore, bifurcation behavior of movable electrode has been investigated.

Multi-Step Operation of Piezoelectric RF-MEMS Tunable Capacitor

2010 ◽  
Vol 130 (6) ◽  
pp. 247-252
Author(s):  
Michihiko Nishigaki ◽  
Toshihiko Nagano ◽  
Hiroshi Ono ◽  
Takashi Kawakubo ◽  
Kazuhiko Itaya
Keyword(s):  
Rf Mems ◽  
Tunable Capacitor

A creep-immune electrostatic actuator for RF-MEMS tunable capacitor

2011 ◽  
Vol 169 (2) ◽  
pp. 373-377 ◽  
Author(s):  
Etsuji Ogawa ◽  
Tamio Ikehashi ◽  
Tomohiro Saito ◽  
Hiroaki Yamazaki ◽  
Kei Masunishi ◽  
...  
Keyword(s):  
Rf Mems ◽  
Electrostatic Actuator ◽  
Tunable Capacitor

CMOS-embedded high-power handling RF-MEMS tunable capacitor using quadruple series capacitor and slit with dielectric bridges structure

2018 ◽  
Vol 57 (10) ◽  
pp. 1002B6
Author(s):  
Hiroaki Yamazaki ◽  
Yoshihiko Kurui ◽  
Tomohiro Saito ◽  
Etsuji Ogawa ◽  
Kei Obara ◽  
...  
Keyword(s):  
High Power ◽  
Rf Mems ◽  
Tunable Capacitor ◽  
Power Handling ◽  
Series Capacitor

scholarly journals Cantilever Beam Metal-Contact MEMS Switch

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Adel Saad Emhemmed ◽  
Abdulmagid A. Aburwein
Keyword(s):  
Cantilever Beam ◽  
Rf Mems ◽  
Spring Constant ◽  
Metal Contact ◽  
Rf Mems Switch ◽  
Microelectromechanical System ◽  
Mems Switch ◽  
Integrated Method ◽  
Beam Geometry ◽  
Contact Switch

We present a new design of a miniature RF microelectromechanical system (MEMS) metal-contact switch and investigate various aspects associated with lowering the pull-down voltage and overcoming the stiction problem. Lowering the pull-down voltage in this design is based on reducing the spring constant by changing the cantilever beam geometry of the RF MEMS switch, and the stiction problem is overcome by a simple integrated method using two tiny posts located on the substrate at the free end of the cantilever beam.

scholarly journals Novel RF MEMS tunable capacitors

2021 ◽  
Author(s):  
Zewdu Hailu
Keyword(s):  
Residual Stress ◽  
Rf Mems ◽  
Stress Gradient ◽  
Repulsive Force ◽  
Quality Factors ◽  
Comb Drive ◽  
Moving Plate ◽  
Tunable Capacitor ◽  
Tunable Capacitors ◽  
Residual Stress Gradient

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%

An Actuator for Controlling the Area of Dielectric Layer of the Tunable Capacitor by Commercial CMOS Fabrication

2003 ◽  
Author(s):  
Jing-Hung Chiou ◽  
Ran-Jin Lin ◽  
Ching-Liang Dai ◽  
Kai-Hsiang Yen ◽  
Yu-Ching Shih ◽  
...  
Keyword(s):  
Cantilever Beam ◽  
Dielectric Layer ◽  
Electrostatic Force ◽  
Complementary Metal Oxide Semiconductor ◽  
Beam Width ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Fixed Plate ◽  
Tunable Capacitor ◽  
Post Process

This study describes the fabrication of an actuator of controlling the area of a dielectric layer using the commercial 0.35μm Single Polysilicon Four Metals (SPFM) Complementary Metal Oxide Semiconductor (CMOS) process and a post-process. The post-process requires wet and dry etching without using a mask to etch sacrificial layers and release the structures suspended in the actuator. The actuator is composed of a top suspended plate, a bottom fixed plate, and a laterally yielding cantilever beam, and two fixed curved electrodes. One end of the cantilever beam is anchored whereas the other end is connected to the suspended plate. The fixed curved electrodes and the cantilever beam are stacked layers of metals and via layers, formed by the CMOS process. The cantilever beam is deflected over a large distance using electrostatic force and the suspended plate swings laterally to increase or decrease the area of overlap between itself and the bottom fixed plate. The dimensions of the actuator are: suspended plate diameter = 100 μm; cantilever beam width = 2 μm, height = 6 μm, and length = 300 μm. The moved end of the cantilever beam, connected to the suspended plate, is deflected by 25 μm when a dc power supply of 60V is applied to it.

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