Fabrication and analysis of radiofrequency MEMS series capacitive single-pole double-throw switch
06 Oct 2016-Journal of Micro-nanolithography Mems and Moems (International Society for Optics and Photonics)-Vol. 15, Iss: 4, pp 045001-045001
TL;DR: In this paper, a single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed, and the critical process parameters are analyzed to improve the fabrication process.
Abstract: A compact radiofrequency (RF) MEMS single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed. The critical process parameters are analyzed to improve the fabrication process. A technique of cold–hot thermal shock for lift-off method is explored. The residual stress in the structure is quantified by lancet test structures that come out to be 51 MPa. Effect of residual stress on actuation voltage is explored, which changes its value from 24 to 22 V. Resonance frequency and switching speed of the switch are 11 kHz and 44 μs, respectively, measured using laser Doppler vibrometer. Measured bandwidth of the SPDT switch is 20 GHz (5 to 25 GHz), which is verified with finite element method simulations in high frequency structure simulator© and an equivalent LCR circuit in advanced design system©. Insertion loss of the switch lies in −0.1 to −0.5 dB with isolation better than −20 dB for the above-mentioned bandwidth.
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12 Dec 2022
TL;DR: In this article , an equivalent circuit modeling of RF MEMS shunt switches based on Artificial Neural Network (ANN) method is presented to determine better RF performance overcomes the disadvantages of the time-consuming optimization processes involved in EM and circuit simulators.
Abstract: Radio Frequency Micro Electro Mechanical System (RF MEMS) are progressing as an enabling technology for designing low loss, high performance, power-efficient switches which are essential in designing modern miniaturized phase shifters for defense radar applications. In this paper, an equivalent circuit modelling of RF MEMS shunt switches based on Artificial Neural Network (ANN) method is presented. The RF performance of MEMS based shunt switch are predicted for different Resistance, Inductance, Capacitance (RLC) combinations. The proposed ANN-based circuit modeling to determine better RF performance overcomes the disadvantages of the time-consuming optimization processes involved in EM and circuit simulators. In this work, the proposed Gradient Descent ANN model minimizes the design time of the equivalent circuit model by 88.8% in comparison with circuit simulator that takes nearly 45 minutes. The validation of the proposed ANN model is done by comparing the obtained results with the Advanced Design System (ADS) model and good agreement is achieved.
25 Jun 2021
TL;DR: In this paper, a shunt capacitive switch based on Radio Frequency MEMS technology is designed for achieving low insertion loss and high isolation in the 5G frequency band, which showed below -14 dB return loss, below -0.20 dB insertion loss, and up to -41 dB isolation at 26 GHz.
Abstract: This paper present low insertion loss and high isolation based switching device. A shunt capacitive switch based on Radio Frequency MEMS technology is designed for achieving the above cited objectives. The device is designed for the frequency range from 24.25 GHz to 27.5 GHz (5G frequency band). The designed switch showed below -14 dB return loss, below -0.20 dB insertion loss and up to -41 dB isolation at 26 GHz. Silicon dioxide having a dielectric constant of 4 is used as a dielectric material. Silicon dioxide layer is deposited above the signal line of CPW to form a capacitor. Au is used for realizing the CPW transmission line and bridge structure. Further, the meanders are used in the switching structure in order to tune the design in the desired frequency range.
07 Aug 2020
TL;DR: In this article, an innovative capacitive radio frequency MEMS shunt switch with a unique shaped spring was designed and analyzed using COMSOL Multiphysics 5.4. The proposed switch using Hafnium oxide (HfO2...
Abstract: An innovative capacitive radio frequency MEMS shunt switch with a unique shaped spring is designed and analyzed using COMSOL Multiphysics 5.4. The proposed switch using Hafnium oxide (HfO2...
Additional excerpts
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References
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Book•
01 Jan 2003
TL;DR: In this paper, the basics of RF MEMS and how to design practical devices and circuits are discussed, as well as expert tips for designers and a range of real-world applications.
Abstract: From the Publisher:
Practical and theoretical coverage of RF MEMS for circuits and devices
New RF and microwave frequency MEMS (microeletromechanical systems) have potentially enormous and widespread applications in the telecommunications industry. Components based on this technologysuch as switches, varactors, and phase shiftersexhibit virtually no power consumption or loss, making them ideally suited for use in modern telecommunications and wireless devices.
This book sets out the basics of RF MEMS and describes how to design practical devices and circuits. As well as covering fundamentals, Gabriel Rebeiz offers expert tips for designers and presents a range of real-world applications. Throughout, the author utilizes actual engineering examples to illustrate basic principles in theory and practice. Detailed discussion of cutting-edge fabrication and packaging techniques is provided.
Suitable as a tutorial for electrical and computer engineering students, or as an up-to-date reference for practicing circuit designers, RF MEMS provides the most comprehensive available survey of this new and important technology.
Author Biography: Gabriel M. Rebeiz received his PhD from the California Institute of Technology, and is Professor of Electrical and Computer Engineering at the University of Michigan, Ann Arbor. In 1991 he was the recipient of the National Science Foundation Presidential Young Investigator Award, and in 2000 was the corecipient of the IEEE Microwave Prize. A Fellow of the IEEE and a consultant to Rockwell, Samsung, Intel, Standard MEMS, and Agilent, he has published extensively in the field of microwave technology and in the area of RF MEMS.
1,895 citations
TL;DR: In this paper, the authors concentrate on electrostatic switches at 0.1-100 GHz with high reliability (100 million to 10 billion cycles) and wafer-scale manufacturing techniques.
Abstract: MEMS switches are devices that use mechanical movement to achieve a short circuit or an open circuit in the RF transmission line. RF MEMS switches are the specific micromechanical switches that are designed to operate at RF-to-millimeter-wave frequencies (0.1 to 100 GHz). The forces required for the mechanical movement can be obtained using electrostatic, magnetostatic, piezoelectric, or thermal designs. To date, only electrostatic-type switches have been demonstrated at 0.1-100 GHz with high reliability (100 million to 10 billion cycles) and wafer-scale manufacturing techniques. It is for this reason that this article will concentrate on electrostatic switches.
1,066 citations
TL;DR: In this article, four major adhesion mechanisms have been analyzed: capillary forces, hydrogen bridging, electrostatic forces and van der Waals forces, and they have been successfully reduced.
Abstract: Due to the smoothness of the surfaces in surface micromachining, large adhesion forces between fabricated structures and the substrate are encountered. Four major adhesion mechanisms have been analysed: capillary forces, hydrogen bridging, electrostatic forces and van der Waals forces. Once contact is made adhesion forces can be stronger than the restoring elastic forces and even short, thick beams will continue to stick to the substrate. Contact, resulting from drying liquid after release etching, has been successfully reduced. In order to make a fail-safe device stiction during its operational life-time should be anticipated. Electrostatic forces and acceleration forces caused by shocks encountered by the device can be large enough to bring structures into contact with the substrate. In order to avoid in-use stiction adhesion forces should therefore be minimized. This is possible by coating the device with weakly adhesive materials, by using bumps and side-wall spacers and by increasing the surface roughness at the interface. Capillary condensation should also be taken into account as this can lead to large increases in the contact area of roughened surfaces.
543 citations
"Fabrication and analysis of radiofr..." refers background in this paper
...The magnitude of stiction forces such as capillary, hydrogen bonding, capacitive charging, and Van der Waal forces are reduced by a factor of nine as these forces are directly proportional to the contact area.(14,15) See-saw configuration has also reduced the number of SPDT switches resulting in an area reduction of more than 85% (actual area 1⁄4 0....
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TL;DR: A review of the mechanics of microscale adhesion in microelectromechanical systems (MEMS) is presented in this article, where dimensionless numbers such as Tabor number, adhesion parameter and peel number for microscale elastic adhesion contact are discussed in detail.
Abstract: A review is presented of the mechanics of microscale adhesion in microelectromechanical systems (MEMS). Some governing dimensionless numbers such as Tabor number, adhesion parameter and peel number for microscale elastic adhesion contact are discussed in detail. The peel number is modified for the elastic contact between a rough surface in contact with a smooth plane. Roughness ratio is introduced to characterize the relative importance of surface roughness for microscale adhesion contact, and three kinds of asperity height distributions are discussed: Gaussian, fractal, and exponential distributions. Both Gaussian and exponential distributions are found to be special cases of fractal distribution. Casimir force induced adhesion in MEMS, and adhesion of carbon nanotubes to a substrate are also discussed. Finally, microscale plastic adhesion contact theory is briefly reviewed, and it is found that the dimensionless number, plasticity index of various forms, can be expressed by the roughness ratio.
410 citations
"Fabrication and analysis of radiofr..." refers background in this paper
...The magnitude of stiction forces such as capillary, hydrogen bonding, capacitive charging, and Van der Waal forces are reduced by a factor of nine as these forces are directly proportional to the contact area.(14,15) See-saw configuration has also reduced the number of SPDT switches resulting in an area reduction of more than 85% (actual area 1⁄4 0....
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TL;DR: In this article, a multilayer SU-8 lift-off technology is proposed for low-cost rapid prototyping of microfluidic devices, which enables the creation of through holes.
Abstract: This paper reports on a novel multilayer SU-8 lift-off technology which allows for low cost rapid prototyping of microfluidic devices. The process presented is based on a multi-layer structure of SU-8 which can be released from the substrate after processing and enables the creation of through holes. The lift-off is accomplished during the development by making use of the volume shrinkage of the SU-8 during postbaking and by modification of the adhesion to the substrate. To demonstrate the technology, prototypes of a multichannel microdispenser according to the Dispensing Well Plate (DWP™) principle (Koltay et al 2004 Sensors Actuators A 116 472, 483) were fabricated. The samples contain 24 parallel dispensing units with 100 µm through holes and a dosage volume of 60 nl. For the first time all functional structures such as reservoirs, channels and through holes (nozzles) of the DWP™ were realized exclusively in the photodefinable epoxy SU-8. To assess the quality of the SU-8 process the geometry of the presented prototypes is characterized by profiler measurements and scanning electron microscopy. Furthermore, the dispensing performance is studied experimentally by gravimetrical measurements. A reproducibility of the dosage volume of 1% and a homogeneity within individual droplet arrays of 3.6% were achieved.
99 citations