Helmholtz Resonance Based Micro Electrostatic Actuators for Compressible Gas Control - A Microjet Generator and a Gas Micro Pump

Aug 25, 2026

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This paper presents Helmholtz-resonance based micro electrostatic actuators designed to control compressible gaseous fluids at the microscale. Two devices are detailed: a micro jet generator and an integrated peristaltic multistage micro pump. High-frequency vibration of a micro membrane enables Helmholtz resonance, repeatedly generating instantaneous pressure that drives rapid gas exit to form a collimated jet and delivers directional momentum. The micro jet generator and 18-stage micro pump are fabricated with low-temperature wafer bonding to protect polymer structures.

LanguageEnglish

CategoryResearch & Report

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Pages9

Reading Time23 min

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Journal of Microelectronics and Electronic Packaging (2010) 7, 1-9 Copyright © International Microelectronics And Packaging Society ISSN: 1551-4897 Helmholtz Resonance Based Micro Electrostatic Actuators for Compressible Gas Control: A Microjet Generator and a Gas Micro Pump Hanseup Kim, 1, * Khalil Najafi,2 and Luis P. Bernal Abstract􀀁This paper reports Helmholtz-resonance based micro electrostatic actuators to control compressible gaseous fluids in the micro scale. Particularly, it discusses design, fabrication, and testing results of two electrostatic actuators: a micro jet generator and an integrated peristaltic multistage micro pump. These electrostatic actuators vibrate a micro membrane in a micro chamber ata high frequency (>10 kHz), and easily induce the resonant behavior of compressible gases in the chamber. Such resonant behavior, often called the Helmholtz resonance, can repeatedly create instantaneous pressure in equilibrium between the inside and outside of the chamber and cause gas to rapidly exit the chamber, forming acollimated jet. The developed micro jet generator consists of multiple acoustic chambers in parallel; produces directional gas momentum from each chamber by utilizing the Helmholtz resonance; and collectively entrains nearby gas molecules to form a gas stream. The fabricated micro jet generator has a footprint of 1.6 3 1.6 cm2 and contains 25 acoustic micro thrusters. It operates using a 140 V and 70 kHz sinusoidal signal and produces a thrust of 55.6 mN, a maximum air velocity of 1.2 m/s, and consumes power of 3.11 mW. The developed micro pump consists of multiple acoustic chambers in series and produces a high total pressure by accumulating pressures across the multiple chambers, while maintaining high flow rates utilizing the fluidic resonance of each pumping chamber. The fabricated 18-stage pump produces the maximum air flow rate of 4.0 sccm and maximum pressure differentials of 17.5 kPa with total power consumptions of only 57 mW. Its total package volume is 25.1 3 19.1 3 1 mm3. It is notable that these electrostatic actuators, with their actuation membranes, acoustic chambers, fluidic channels, and micro valves, are fabricated into a single silicon chip by developing low temperature wafer bonding techniques to protect the polymer structures inside. Keywords􀀁Micro actuator, electrostatic actuation, Helmholtz resonance, microjet generator, gas micro pump, gas compressibility INTRODUCTION Recent electronic devices have increasingly incorporated interfacing capability with nonelectrical environments to enhance information collection, decision-making, and even environmental stimulation abilities. Such interface allows once-computation-limited electronic devices to interact with Manuscript received December 2009 and accepted March 2010 1Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84108 2Center for Wireless Integrated Microsystems, University of Michigan, Ann Arbor, Michigan 48109 *Corresponding author; [email: hanseup@ece.utah.edu](email: hanseup@ece.utah.edu) physical environments, augment their decision-making process with direct monitoring of physical surroundings, and thus easily bridge multiple information domains, such as mechanical, thermal, optical, and fluidic to electrical. For example, the interface to human nerve systems, such as EMG (electromyogram of the muscle), ECG (electrocardiogram of the heart), ERG (electroretinogram of the retina), EOG (electrooculogram of the eye), and EEG (electroencephalogram of the brain), has allowed numerous streams of nonelectrical bio-information to be in situ monitored by computing systems [1] . The recent revolutionary Nitendo Wii game consoles have included motion sensors to react to delicate movements of users and enabled responsive interaction of computing-based software. Among several domains, an interface with fluids has been increasingly pursued, particularly in the microscale, due to t

FAQs

How does Helmholtz resonance contribute to gas control in the chamber?

Helmholtz resonance repeatedly creates instantaneous equilibrium pressure between the chamber interior and exterior, causing gas to exit quickly and form a collimated jet while supporting pumping action.

Aug 25, 2026

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