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 - Kaiser, Bert A1 - Grashoff, Thomas A1 - Drabe, Christian A1 - Conrad, Holger A1 - Schenk, Harald T1 - About stress in filled DRIE-trenches T2 - Journal of Micromechanics and Microengineering (JMM) Y1 - 2015 UR - http://iopscience.iop.org/article/10.1088/0960-1317/25/8/085003 SN - 0960-1317 VL - 25 IS - 8 SP - 8085003 ER - TY - PAT A1 - Conrad, Holger A1 - Schenk, Harald A1 - Schirrmann, Christian A1 - Zimmer, Fabian A1 - Schmidt, Jan-Uwe A1 - Sandner, Thilo T1 - Micromechanical element Y1 - 2015 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 - 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 - PAT A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schenk, Harald A1 - Uhlig, Sebastian T1 - Mikromechanical devices with mechanical actuators T1 - Mikromechanische Bauelemente mit mechanischen Aktuatoren Y1 - 2018 ER - TY - PAT A1 - Schenk, Harald A1 - Conrad, Holger T1 - MEMS-Wandler zum Interagieren mit einem Volumenstrom eines Fluids und Verfahren zum Herstellen desselben T1 - MEMS converter for interacting with a volume flow of a fluid and method of manufacturing the same Y1 - 2018 ER - TY - GEN A1 - Ehrig, Lutz A1 - Kaiser, Bert A1 - Conrad, Holger A1 - Schenk, Hermann A1 - Schuffenhauer, David A1 - Stolz, Michael A1 - Gaudet, Matthieu A1 - Schenk, Harald A1 - Kolkovsky, Vladimir T1 - MEMS-Loudspeaker - A Novel Class of Electroacoustic Transducers for Mobile Audio Applications T2 - Tonmeistertagung - VDT International Convention, Cologne, Germany, 2018, Proc. TMT 30 N2 - Wireless earphones require a tremendous degree of integration: In addition to the electroacoustic transducer at least the power supply and a radio module have to be accommodated, supplemented by several microphones for hands-free applications or for noise reduction, as well as position and bio sensors, memory and CPU. With increasing integration, the pressure on the individual components increases in terms of size, energy efficiency and costs. In the field of microphones, MEMS technology has enjoyed great popularity for almost 10 years, and due to their benefits (size, cost, integration) MEMS microphones have almost completely supersede other microphone technologies in mobile audio devices and opened up new fields of applications. Y1 - 2018 VL - TMT 30 SP - 189 EP - 192 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 - 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 - Monsalve Guaracao, Jorge Mario A1 - Melnikov, Anton A1 - Kaiser, Bert A1 - Schuffenhauer, David A1 - Stolz, Michael A1 - Ehrig, Lutz A1 - Schenk, Hermann A1 - Conrad, Holger A1 - Schenk, Harald T1 - Large-Signal Equivalent-Circuit Model of Asymmetric Electrostatic Transducers T2 - IEEE/ASME Transactions on Mechatronics N2 - This article presents a circuit model that is able to capture the full nonlinear behavior of an asymmetric electrostatic transducer whose dynamics are governed by a single degree of freedom. Effects such as stress-stiffening and pull-in are accounted for. The simulation of a displacement-dependent capacitor and a nonlinear spring is accomplished with arbitrary behavioral sources, which are a standard component of circuit simulators. As an application example, the parameters of the model were fitted to emulate the behavior of an electrostatic MEMS loudspeaker whose finite-element (FEM) simulations and acoustic characterisation where already reported in the literature. The obtained waveforms show good agreement with the amplitude and distortion that was reported both in the transient FEM simulations and in the experimental measurements. This model is also used to predict the performance of this device as a microphone, coupling it to a two-stage charge amplifier. Additional complex behaviors can be introduced to this network model if it is required. KW - Acoustic transducers KW - Duffing oscillator KW - Acoustic electrostatic actuators KW - equivalent-circuit model KW - microactuators KW - Electrostatics KW - Transducers KW - Mathematical models KW - Integrated circuit modeling KW - Capacitors KW - Microphones KW - Force Y1 - 2021 U6 - https://doi.org/10.1109/TMECH.2021.3112267 SN - 1083-4435 SN - 1941-014X VL - 7 IS - 5 SP - 2612 EP - 2622 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 - PAT A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schenk, Harald A1 - Uhlig, Sebastian T1 - Micromechanical devices with mechanical actuators Y1 - 2023 UR - https://www.freepatentsonline.com/11639718.html ER - TY - PAT A1 - Schenk, Harald A1 - Conrad, Holger T1 - MEMS transducer for interacting with a volume flow of a fluid, and method for producing the same Y1 - 2023 UR - https://www.freepatentsonline.com/11554950.html ER - TY - PAT A1 - Schenk, Harald A1 - Conrad, Holger A1 - Gaudet, Matthieu A1 - Schimmanz, Klaus A1 - Langa, Sergiu A1 - Kaiser, Bert T1 - MEMS transducer for interacting with a volume flow of a fluid and method for manufacturing the same N2 - A MEMS transducer for interacting with a volume flow of a fluid includes a substrate including a cavity, and an electromechanical transducer connected to the substrate in the cavity and including an element deformable along a lateral movement direction, wherein a deformation of the deformable element along the lateral movement direction and the volume flow of the fluid are causally related. Y1 - 2025 ER -