TY - GEN A1 - Langa, Sergiu A1 - Drabe, Christian A1 - Kunath, Christian A1 - Dreyhaupt, André A1 - Schenk, Harald T1 - Wafer level vacuum packaging of scanning micro-mirrors using glass-frit and anodic bonding methods T2 - SPIE Conference MOEMS and Miniaturized Systems XII, San Francisco, 2013 Y1 - 2013 SN - 978-0-8194-9385-9 U6 - https://doi.org/10.1117/12.2003525 SP - 86140F-1 EP - 86140F-8 PB - SPIE CY - Bellingham, Wash. ET - 1. Auflage ER - TY - PAT A1 - Langa, Sergiu A1 - Conrad, Holger A1 - Schenk, Harald A1 - Stolz, Michael T1 - Elektrostatisch auslenkbares mikromechanisches Bauelement Y1 - 2014 ER - TY - GEN A1 - Conrad, Holger A1 - Schenk, Harald A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Gaudet, Matthieu A1 - Schimmanz, Klaus A1 - Stolz, Michael A1 - Lenz, Miriam T1 - A small-gap electrostatic micro-actuator for large deflections T2 - Nature Communications Y1 - 2015 U6 - https://doi.org/10.1038/ncomms10078 SN - 2041-1723 IS - 6 SP - 10078 ER - TY - GEN A1 - Kolkovsky, Vladimir A1 - Stübner, R. A1 - Langa, Sergiu A1 - Wende, U. A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald T1 - Influence of annealing in H atmosphere on the electrical properties of Al₃O₃ layers grown on p-type Si by the atomic layer deposition technique T2 - Solid-State Electronics Y1 - 2016 U6 - https://doi.org/10.1016/j.sse.2016.06.005 SN - 0038-1101 VL - 123 SP - 89 EP - 95 ER - TY - GEN A1 - Conrad, Holger A1 - Kaiser, Bert A1 - Gaudet, Matthieu A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Uhlig, Sebastian A1 - Schimmanz, Klaus A1 - Schenk, Harald T1 - A novel electrostatic actuator class T2 - Procedia Engineering Y1 - 2016 U6 - https://doi.org/10.1016/j.proeng.2016.11.454 SN - 1877-7058 VL - 168 SP - 1533 EP - 1536 ER - TY - CHAP A1 - Schenk, Harald A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Schimmanz, Klaus T1 - A novel electrostatic micro-actuator class and its application potential for optical MEMS T2 - 2016 International Conference on Optical MEMS and Nanophotonics,31 July-04 August 2016, Singapore, proceedings Y1 - 2016 SN - 978-1-5090-1036-3 U6 - https://doi.org/10.1109/OMN.2016.7565867 SP - Tu 3.11-1 EP - Tu 3.11-2 PB - IEEE CY - Piscataway, NJ ER - TY - PAT A1 - Schenk, Harald A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schimmanz, Klaus A1 - Langa, Sergiu A1 - Kaiser, Bert T1 - MEMS-Wandler zum Interagieren mit einem Volumenstrom eines Fluids und Verfahren zum Herstellen desselben T2 - MEMS transducer for interacting with a volume flow of a fluid and method of manufacturing the same Y1 - 2015 ER - TY - CHAP A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Stolz, Michael A1 - Arscott, S. A1 - Conrad, Holger A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Electrostatic bending actuators with liquid filled nanometer scale gap T2 - MEMS 2017, the 30th IEEE International Conference on Micro Electro Mechanical Systems, Las Vegas, Nevada, USA, January 22-26 2017 Y1 - 2017 UR - http://ieeexplore.ieee.org/document/7863369/ SN - 978-1-5090-5078-9 SN - 978-1-5090-5079-6 SP - 175 EP - 178 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Schenk, Harald A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Schimmanz, Klaus T1 - A contribution to the expansion of the applicability of electrostatic forces in micro transducers T2 - MOEMS and Miniaturized Systems XVI, 30 January-1 February 2017, San Francisco, California, United States Y1 - 2017 SN - 978-1-5106-0674-6 SN - 978-1-5106-0673-9 U6 - https://doi.org/10.1117/12.2249575 PB - SPIE CY - Bellingham, Washington, USA ER - TY - GEN A1 - Langa, Sergiu A1 - Conrad, Holger A1 - Kaiser, Bert A1 - Stolz, Michael A1 - Gaudet, Matthieu A1 - Uhlig, Sebastian A1 - Schimmanz, Klaus A1 - Schenk, Harald T1 - Technological aspects of a new micro-electro-mechanical actuation principle: nano e-drive T2 - Microsystem Technologies Y1 - 2017 U6 - https://doi.org/10.1007/s00542-017-3360-6 SN - 1432-1858 VL - 23 IS - 1 SP - 5697 EP - 5708 ER - TY - GEN A1 - Uhlig, Sebastian A1 - Gaudet, Matthieu A1 - Langa, Sergiu A1 - Schimmanz, Klaus A1 - Conrad, Holger A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Electrostatically driven in-plane silicon micropump for modular configuration T2 - Micromachines N2 - In this paper, an in-plane reciprocating displacement micropump for liquids and gases which is actuated by a new class of electrostatic bending actuators is reported. The so-called “Nano Electrostatic Drive” is capable of deflecting beyond the electrode gap distance, enabling large generated forces and deflections. Depending on the requirements of the targeted system, the micropump can be modularly designed to meet the specified differential pressures and flow rates by a serial and parallel arrangement of equally working pumping base units. Two selected, medium specific micropump test structure devices for pumping air and isopropanol were designed and investigated. An analytical approach of the driving unit is presented and two-way Fluid-Structure Interaction (FSI) simulations of the micropump were carried out to determine the dynamic behavior. The simulation showed that the test structure device designed for air expected to overcome a total differential pressure of 130 kPa and deliver a flow rate of 0.11 sccm at a 265 Hz driving frequency. The isopropanol design is expected to generate 210 kPa and pump 0.01 sccm at 21 Hz. The device is monolithically fabricated by CMOS-compatible bulk micromachining processes under the use of standard materials only, such as crystalline silicon, silicon dioxide and alumina. KW - micropump; electrostatic actuation; nano e-drive; in-plane reciprocating displacement micropump; MEMS Y1 - 2018 U6 - https://doi.org/10.3390/mi9040190 SN - 2072-666X VL - 9 IS - 4 ER - TY - CHAP A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Schenk, Harald T1 - CMOS-kompatible elektrostatische Biegeaktoren (CMOS-compatible electrostatic actuators T2 - MikroSystemTechnik Kongress 2017, München, Germany, 23.-25. Oktober 2017 Y1 - 2017 SN - 978-3-8007-4491-6 SP - 219 EP - 222 PB - VDE-Verlag CY - Berlin [u.a.] ER - TY - CHAP A1 - Uhlig, Sebastian A1 - Gaudet, Matthieu A1 - Langa, Sergiu A1 - Schimmanz, Klaus A1 - Conrad, Holger A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Electrostatically in-plane driven silicon micropump for modular configuration T2 - Conference proceedings, The 3rd Conference on MicroFluidic Handling Systems (MFHS 2017), 4 - 6 October 2017, Enschede, The Netherlands Y1 - 2017 UR - http://publica.fraunhofer.de/dokumente/N-477736.html SP - 57 EP - 60 PB - University of Twente CY - Enschede ER - TY - GEN A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Ehrig, Lutz A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schenk, Harald T1 - Optische Charakterisierungsmethoden von siliziumbasierten MEMS mit verdeckten Strukturen T2 - MikroSystemTechnik-Kongress, Berlin, Germany, 2019 N2 - In der Arbeitsgruppe integrierte Siliziumsysteme des Fraunhofer IPMS werden am Standort Cottbus innovative Anwen-dungen eines neuartigen nanoskopischen elektrostatischen Antriebs (nanoskopic electrostatic drive – NED) untersucht. Eine der vielversprechendsten Anwendungen sind Lautsprecher. Vollständig aus Silizium gefertigte MEMS-Lautsprecher auf Basis von NED-Biegeaktoren werden vor den akustischen Messungen mechanisch und elektrisch cha-rakterisiert. Beidseitig eingespannte elektrostatisch betriebene in-plane NED-Aktoren werden dabei über einen Fre-quenzbereich von 20 Hz bis 20 kHz angeregt. Dabei sind die Strukturen oft verdeckt, was ihre Charakterisierung er-schwert. Es werden zerstörungsfreie optische Methoden präsentiert, mit deren Hilfe die Bestimmung der mechanischen Schwingungseigenschaften einzelner Aktoren ermöglicht wird sowie die Beweglichkeit im verdeckten Zustand nach-gewiesen werden kann. Y1 - 2019 UR - https://www.ipms.fraunhofer.de/de/events/2019/mst-kongress.html SP - 366 EP - 369 PB - VDE-Verlag ER - TY - GEN A1 - Spitz, Barbara A1 - Wall, Franziska A1 - Schenk, Hermann A1 - Melnikov, Anton A1 - Ehrig, Lutz A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald A1 - Pufe, Wolfram T1 - Audio-Transducer für In-Ear-Anwendungen auf der Basis CMOS-kompatibler, elektrostatischer Biegeaktoren T2 - MikroSystemTechnik-Kongress, Berlin, Germany, 2019 N2 - Recently an innovative mSpeaker technology, based on a novel kind of CMOS compatible small gap electrostatic actuators for large deflection, has been introduced [1]. In this paper, we devise methods to model such speakers in terms of lumped parameters using the deflection of the beam centre as sole dynamic variable. Optical, acoustical and finite element methods (FEM) are used to validate the non-linear lumped parameter model (LPM). The experimental evaluation and LPM simulations of the total harmonic distortion reveal deeper insights into the mechanisms governing linearity. Y1 - 2019 SP - 54 EP - 57 PB - VDE-Verlag ER - TY - GEN A1 - Kaiser, Bert A1 - Langa, Sergiu A1 - Ehrig, Lutz A1 - Stolz, Michael A1 - Schenk, Hermann A1 - Conrad, Holger A1 - Schenk, Harald A1 - Schimmanz, Klaus A1 - Schuffenhauer, David T1 - Concept and proof for an all-silicon MEMS micro speaker utilizing air chambers T2 - Microsystems and Nanoengineering N2 - MEMS-based micro speakers are attractive candidates as sound transducers for smart devices, particularly wearables and hearables. For such devices, high sound pressure levels, low harmonic distortion and low power consumption are required for industrial, consumer and medical applications. The ability to integrate with microelectronic circuitry, as well as scalable batch production to enable low unit costs, are the key factors benchmarking a technology. The Nanoscopic Electrostatic Drive based, novel micro speaker concept presented in this work essentially comprises in-plane, electrostatic bending actuators, and uses the chip volume rather than the its surface for sound generation. We describe the principle, design, fabrication, and first characterization results. Various design options and governing equations are given and discussed. In a standard acoustical test setup (ear simulator), a MEMS micro speaker generated a sound pressure level of 69 dB at 500 Hz with a total harmonic distortion of 4.4%, thus proving the concept. Further potential on sound pressure as well as linearity improvement is outlined. We expect that the described methods can be used to enhance and design other MEMS devices and foster modeling and simulation approaches. Y1 - 2019 U6 - https://doi.org/10.1038/s41378-019-0095-9 SN - 2055-7434 IS - 5 ER - TY - GEN A1 - Ehrig, Lutz A1 - Kaiser, Bert A1 - Schenk, Hermann A1 - Stolz, Michael A1 - Langa, Sergiu A1 - Conrad, Holger A1 - Schenk, Harald A1 - Männchen, Andreas A1 - Brocks, Tobias T1 - Acoustic validation of electrostatic all-silicon MEMS-speakers T2 - AES International Conference on Headphone Technology, San Francisco, New York, USA, 2019 Y1 - 2019 UR - https://www.aes.org/e-lib/browse.cfm?elib=20522 U6 - https://doi.org/10.17743/aesconf.2019.978-1-942220-29-9 ER - TY - GEN A1 - Ehrig, Lutz A1 - Schenk, Hermann A1 - Wall, Franziska A1 - Melnikov, Anton A1 - Stolz, Michael A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald T1 - Electrostatic all silicon MEMS speakers for in-ear audio applications – acoustic measurements and modelling approach T2 - 23rd International Congress on Acoustics, Aachen, Germany, 2019 Y1 - 2019 U6 - https://doi.org/10.18154/RWTH-CONV-239893 ER - TY - GEN A1 - Melnikov, Anton A1 - Schenk, Hermann A1 - Wall, Franziska A1 - Spitz, Barbara A1 - Ehrig, Lutz A1 - Langa, Sergiu A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Harald A1 - Stolz, Michael T1 - Minimization of nonlinearities in nano electrostatic drive actuators using validated coupled-field simulation T2 - SPIE Conference: MOEMS and Miniaturized Systems XIX, San Francisco, USA, 2020, Proc. SPIE 11293 Y1 - 2020 U6 - https://doi.org/10.1117/12.2551271 ER - TY - GEN A1 - Schenk, Harald A1 - Stolz, Michael A1 - Langa, Sergiu A1 - Kaiser, Bert T1 - Reliability Aspects of in-plane NED Bending Actuators in Silicon-based MEMS T2 - MikroSystemTechnik Kongress 2021 : Mikroelektronik / Mikrosystemtechnik und ihre Anwendungen Innovative Produkte für zukunftsfähige Märkte 08. – 10. November 2021, Stuttgart-Ludwigsburg N2 - For several years, Fraunhofer IPMS has been developing a new type of an electrostatic MEMS actuator, called nanoscopic electrostatic drive - NED. Since the first publication in 2015, the project group at IPMS has succeeded in providing lateral actuators, which serve as innovative drives in applications such as micro-positioners or micro-speakers. These applications require a high long-term stability of the drive in order to ensure that the system operates as desired. For this purpose, the reliability of such novel lateral electrostatic actuators was evaluated. Long-term studies of NED actuators have shown that different degradation phenomena can occur during operation. The experiments indicate that high electric fields in the range of several MV/m are one of the most important triggers of the degradations observed. On the one hand, they lead to anodic oxidation occurring at the boundary layers between the NED electrodes and neighbored insulators, which results in corrosion of the silicon electrodes. On the other hand, geometry-based field enhancement far from the insulator interfaces lead to permanent field emission, which causes dark discharges in the electrode gap. This in turn leads to cold plasma oxidation and the growth of oxide b ulges on the electrode surfaces. In the course of the experiments, it was shown that corrosion does not take place in a vacuum and can be avoided with the help of passivation layers. Non silicon oxides, e.g. Al2O3, are well suited as passivation layers. Although they bring additional flexural rigidity to the overall structure, which changes the mechanical behavior of the actuators, they increase the effective relative permittivity in the electrode gap, which in turn makes the actuators more effective. Thanks to the passivation coating,the lifespan of the NED actuators was increased and they can become even more effective by choosing a layer with suitable properties. Y1 - 2021 UR - https://www.vde-verlag.de/proceedings-de/455656134.html SN - 978-3-8007-5656-8 SN - 978-3-8007-5657-5 PB - VDE-Verlag ER - TY - GEN A1 - Schenk, Harald A1 - Narimani, Keyvan A1 - Scholles, Michael A1 - Shashank, Shashank A1 - Langa, Sergiu A1 - Pineda Gomez, Roberto A1 - Ruffert, Christine T1 - Highly Modular Microsystem Inchworm Motor Based on a Nanoscopic Electrostatic Drive T2 - MikroSystemTechnik Kongress 2021 : Mikroelektronik / Mikrosystemtechnik und ihre Anwendungen Innovative Produkte für zukunftsfähige Märkte 08. – 10. November 2021, Stuttgart-Ludwigsburg N2 - We present results for a microsystem inchworm motor based on Nanoscopic Electrostatic Drive (NED) actuators, fabricated by single crystalline silicon bulk micro-machining on a silicon-on-insulator (SOI) wafer. Actuator elements can easily be added to or removed from the inchworm drive allowing a high adaptability of force and contact area with the movable surface as well as an efficient use of the system’s footprint. In principle, travel ranges of several mm can be easily obtained due to very modular design of the system. The presented inchworm drive is capable of controllable motion up to 1 mm and can generate a force of 1.4 mN at 130V corresponding to a force density of 0.8 mN/mm2 with an average maximum DC power consumption of 11.8 muW in each cycle. Furthermore, the voltage-displacement characteristics of the actuator element was validated by finite element method (FEM). Y1 - 2021 UR - https://www.vde-verlag.de/proceedings-de/455656160.html SN - 978-3-8007-5656-8 SN - 978-3-8007-5657-5 PB - VDE e.V. ER - TY - GEN A1 - Schenk, Harald A1 - Melnikov, Anton A1 - Stolz, Michael A1 - Wall, Franziska A1 - Kaiser, Bert A1 - Mrosk, Andreas A1 - Schuffenhauer, David A1 - Monsalve Guaracao, Jorge Mario A1 - Langa, Sergiu A1 - Schenk, Hermann A1 - Ehrig, Lutz A1 - Conrad, Holger A1 - Ahnert, Maik T1 - Nonlinearity of balanced MEMS loudspeakers: optical experiments and numerical modeling using time-harmonic signals T2 - 27th International Congress on Sound and Vibration, Annual Congress of International Institute of Acoustics and Vibration (IIAV) N2 - A recently introduced novel actuator class, called the nano electrostatic drive (NED), uses the elec-trostatic actuation to generate large deflections of elastic structures. The NED principle was recently successfully applied to create an all silicon loudspeaker based on micro-electro-mechanical systems (MEMS) technology. Such MEMS audio transducers cover the full frequency range required for high fidelity audio applications. High fidelity audio reproduction also demands minimizing harmonic distortions substantially below 1 %. A major advance in this direction is combining the NED principle with a push-pull driving scheme in a balanced design (BNED), eliminating even harmonics. The practical implementation of a BNED design is however demanding. The nature of the Coulomb force, the impact of stress stiffening and the large deformations required for generating high sound pressures, to name a few aspects, potentially contribute to the harmonic distortion and therefore need advanced experimental methods and simulation models to allow for an apt design. In this paper, we report first results of an experimental technique, combining an optical microscope with a high-speed camera, capable of analyzing the local details of the actuator movement at frame rates of 50,000 frames per second. Dynamic features, such as the excitation of harmonics and intermodulations become clearly visible. These experimental results are then used to scrutinize and refine our multi physics FEM simulations. Y1 - 2021 UR - https://www.researchgate.net/publication/354465569_Nonlinearity_of_balanced_MEMS_loudspeakers_optical_experiments_and_numerical_modeling_using_time-harmonic_signals ER - TY - GEN A1 - Kaiser, Bert A1 - Schenk, Hermann A. G. A1 - Ehrig, Lutz A1 - Wall, Franziska A1 - Monsalve Guaracao, Jorge Mario A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Melnikov, Anton A1 - Conrad, Holger A1 - Schuffenhauer, David A1 - Schenk, Harald T1 - The push-pull principle: an electrostatic actuator concept for low distortion acoustic transducers T2 - Microsystems & Nanoengineering N2 - Electrostatic actuators are of particular interest for microsystems (MEMS), and in particular for MEMS audio transducers for use in advanced true wireless applications. They are attractive because of their typically low electrical capacitance and because they can be fabricated from materials that are compatible with standard complementary metal-oxide semiconductor (CMOS) technology. For high audio performance and in particular low harmonic distortion (THD) the implementation of the push-pull principle provides strong benefits. With an arrangement of three electrodes in a conjunct moving configuration on a beam, we demonstrate here for the first time a balanced bending actuator incarnating the push-pull principle operating at low voltages. Our first design already exhibits a harmonic distortion as low as 1.2% at 79 dB using a signal voltage of only 6 Vp and a constant voltage of only ±10 Vdc in a standard acoustic measurement setup. Thus, exceeding our previously reported approach in all three key performance indications at the same time. We expect that our novel electrode configurations will stimulate innovative electrostatic actuator developments for a broad range of applications. In this paper we report the basic theory, the fabrication and the performance of our novel actuator design acting as an audio transducer. Y1 - 2022 U6 - https://doi.org/10.1038/s41378-022-00458-z SN - 2055-7434 VL - Vol. 8 ER - TY - GEN A1 - Monsalve Guaracao, Jorge Mario A1 - Melnikov, Anton A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Jongmanns, Marcel A1 - Wall, Franziska A1 - Langa, Sergiu A1 - Marica-Bercu, Ioana A1 - Brändel, Tim A1 - Kircher, Marco A1 - Schenk, Hermann A. G. A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Proof of concept of an air-coupled electrostatic ultrasonic transducer based on lateral motion T2 - Sensors and Actuators A: Physical N2 - An alternative implementation of an electrostatic MUT (Micromachined Ultrasonic Transducer), relying on multiple beams that displace along the chip’s surface instead of a single membrane displacing perpendicular to it, is presented in this work. With this approach, a design requiring a low bias voltage (24 V) and occupying a small area (3.3×3.3 mm², 2D/λ≈0.77) was shown to generate a sound pressure level of 82 dB (re. 20 µPa-rms) at 40 kHz and a distance of 8.9 cm. The high level of damping allows this transducer to operate in a wide frequency range (35-63 kHz). The operation of this device as an ultrasonic receiver was also proven. An implementation of this transducer as a rangefinder requires a strong reduction in the noise level, particularly coming from radio-frequency interference, in order to increase its detection range. Y1 - 2022 U6 - https://doi.org/10.1016/j.sna.2022.113813 SN - 1873-3069 SN - 0924-4247 VL - Vol. 345 ER - TY - GEN A1 - Ruffert, Christine A1 - Schenk, Hermann A. G. A1 - Kaiser, Bert A1 - Ehrig, Lutz A1 - Monsalve Guaracao, Jorge Mario A1 - Langa, Sergiu A1 - Wall, Franziska A1 - Melnikov, Anton A1 - Stolz, Michael A1 - Morsk, Andreas A1 - Schuffenhauer, David A1 - Conrad, Holger A1 - Schenk, Harald T1 - Elektrostatischer Gegentakt NED-Aktor für Im-Ohr-µLautsprecher Y1 - 2023 UR - https://publica.fraunhofer.de/entities/publication/af8b72ee-2b53-4478-a964-a9dfb17ac3ad/details U6 - https://doi.org/10.24406/publica-2553 N1 - Im Rahmen der Mittelstandskonferenz 2023 in Berlin präsentiert. ER - TY - GEN A1 - Ruffert, Christine A1 - Jongmanns, Marcel A1 - Kaiser, Bert A1 - Langa, Sergiu T1 - Design and characterization of a silicon MEMS microvalve for proportional flow control based on electrostatic bending actuators T2 - Microsystem Technologies N2 - We designed a MEMS microvalve based on the nanoscopic electrostatic drive (NED) technology (Nat Commun 6:10078, 2015). NED actuators, electrostatically controlled bending beams, are implemented in a clamped-clamped configuration. A normally open plunger valve was designed and characterized. The device is manufactured from silicon. Gas flow rates of up to 37 SCCM can be proportionally controlled between 10% and 100%. A 10% leakage is always present at low backpressures (< 10 kPa) and increases to roughly 20% at 75 kPa backpressure. The structure has been tested up to backpressures of 300 kPa without damage to the structures, but the leakage increases to over 95%. Our unprecedented microvalve concept shows that it is possible to manufacture all-silicon MEMS microvalves with proportional control of the flow rate. The presented work is a proof of concept to test the capabilities of the NED technology for the use in microvalves. There are plans to decrease the leakage in future designs by introducing an additional sealing layer as well as manufacturing a shutter instead of a plunger design. Y1 - 2024 U6 - https://doi.org/10.1007/s00542-024-05684-1 SN - 1432-1858 SN - 0946-7076 VL - 2024 ER - TY - GEN A1 - Ruffert, Christine A1 - Monsalve Guaracao, Jorge Mario A1 - Völz, Uwe A1 - Jongmanns, Marcel A1 - Betz, Björn A1 - Langa, Sergiu A1 - Amelung, Jörg A1 - Wiersig, Marcus T1 - Rapid characterisation of mixtures of hydrogen and natural gas by means of ultrasonic time-delay estimation T2 - Journal of Sensors and Sensor Systems N2 - The implementation of the “power-to-gas” concept, where hydrogen and natural gas are blended and transported in the existing network, requires a quick, on-site method to monitor the content of hydrogen in the mixture. We evaluate a rapid characterisation of this mixture based on the measurement of the speed of sound, using micromachined ultrasonic transducers (MUTs). Two MUT-based prototypes were implemented to analyse a mixture of natural gas and hydrogen under controlled conditions. Changes in the hydrogen content below 2 mol % (in a mixture that was adjusted between 6 mol % and 16 mol %) were discriminated by both devices, including the uncertainty due to the temperature compensation and the time-delay estimation. The obtained values of the speed of sound were consistent with those calculated from independent, non-acoustic measurements performed with a gas chromatograph and a density sensor. An MUT-based flow meter is thus capable of reporting both gas intake and the molar fraction of hydrogen, provided that the source of natural gas is kept constant. Y1 - 2024 U6 - https://doi.org/10.5194/jsss-13-179-2024 SN - 2194-878X VL - 13 IS - 2 SP - 185 ER - TY - GEN A1 - Uhlig, Sebastian A1 - Gaudet, Matthieu A1 - Langa, Sergiu A1 - Ruffert, Christine A1 - Jongmanns, Marcel A1 - Schenk, Harald T1 - Highly integrable silicon micropumps using lateral electrostatic bending actuators T2 - Microsystem Technologies N2 - We present the design, fabrication, and characterization of an innovative silicon-based micropump with high potential for portable lab-on-chip (LoC) as well as point-of-care (PoC) applications. The actuators of the pump are electrostatic driven in-plane bending devices, which were presented earlier (Borcia et al. in Phys Rev Fluids 3(8): 084202, 2018. 10.1103/PhysRevFluids.3.084202; Uhlig et al. in Micromachines, 9(4), 2018. 10.3390/mi9040190). This paper presents the characterization results achieved with the micropump. The dielectric non-polar liquid Novec7100™ was used as a test liquid due to its adequate physical properties. When applying a periodic voltage of 130 V, a flow rate of up to 80 µL/min was detected. The counter pressure amounts up to 30 kPa and the correspondent fluidic power (volumetric flow rate times the counter pressure) was calculated to 10 µW. The pump contains passive flap valves at the inlet and outlet, which are based on a bending cantilever design. Depending on the application requirements, the micropump can be designed modularly to adjust the specific parameters by an adequate arrangement of pump base units. In this paper, the proof of principle is shown using a single base unit with different number of stacked NED-actuator beams, as well as the serial arrangement of base units. Both modular concepts target the increase of backpressure of the NED-micropump in an inherently different way compared to conventional membrane micropumps. Y1 - 2024 U6 - https://doi.org/10.1007/s00542-024-05635-w SN - 0946-7076 VL - 30 IS - 8 SP - 949 EP - 960 PB - Springer Science and Business Media LLC ER - TY - GEN A1 - Guaraco, Jorge Mario Monsalve A1 - Langa, Sergiu A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Kaiser, Bert A1 - Schenk, Harald T1 - Design of micromachines under uncertainty with the sample-average approximation method T2 - Journal of Advanced Mechanical Design, Systems, and Manufacturing Y1 - 2024 U6 - https://doi.org/10.1299/jamdsm.2024jamdsm0018 SN - 1881-3054 VL - 18 (2024) IS - 2 PB - Japan Society of Mechanical Engineers ER - TY - GEN A1 - Melnikov, Anton A1 - Schenk, Hermann A. G. A1 - Monsalve Guaracao, Jorge Mario A1 - Wall, Franziska A1 - Stolz, Michael A1 - Mrosk, Andreas A1 - Langa, Sergiu A1 - Kaiser, Bert T1 - Coulomb-actuated microbeams revisited: experimental and numerical modal decomposition of the saddle-node bifurcation T2 - Microsystems & Nanoengineering N2 - Electrostatic micromechanical actuators have numerous applications in science and technology. In many applications, they are operated in a narrow frequency range close to resonance and at a drive voltage of low variation. Recently, new applications, such as microelectromechanical systems (MEMS) microspeakers (µSpeakers), have emerged that require operation over a wide frequency and dynamic range. Simulating the dynamic performance under such circumstances is still highly cumbersome. State-of-the-art finite element analysis struggles with pull-in instability and does not deliver the necessary information about unstable equilibrium states accordingly. Convincing lumped-parameter models amenable to direct physical interpretation are missing. This inhibits the indispensable in-depth analysis of the dynamic stability of such systems. In this paper, we take a major step towards mending the situation. By combining the finite element method (FEM) with an arc-length solver, we obtain the full bifurcation diagram for electrostatic actuators based on prismatic Euler-Bernoulli beams. A subsequent modal analysis then shows that within very narrow error margins, it is exclusively the lowest Euler-Bernoulli eigenmode that dominates the beam physics over the entire relevant drive voltage range. An experiment directly recording the deflection profile of a MEMS microbeam is performed and confirms the numerical findings with astonishing precision. This enables modeling the system using a single spatial degree of freedom. KW - Engineering KW - NEMS KW - Sensors Y1 - 2021 U6 - https://doi.org/10.1038/s41378-021-00265-y SN - 2055-7434 VL - 7 IS - 1 ER -