An official website of the United States government
Microfluidically reconfigurable radio-frequency (RF) devices in general have been found attractive for low-loss, wide-frequency tunability and high-power-handling capabilities. Recently, integrated actuation of the microfluidically reconfigurable devices has been proposed for compact mm-wave device applications. This article for the first time introduces microfluidically reconfigurable frequency- and/or bandwidthtunable bandpass filters (BPFs) operated at the mm-wave band with integrated actuation. The BPFs consist of coupled hairpin resonators. Frequency tuning is achieved by capacitively loading the resonators. Bandwidth tuning is achieved by creating varying capacitive loading among the resonators to control the interresonator couplings. The capacitive loading mechanisms are realized using the selectively metallized plates (SMPs) that can be repositioned within the microfluidic channels. The microfluidic channels are located directly above the stationary metallizations of the filter. Piezoelectric bending actuators placed under the filter’s ground plane provide the SMP motion capability. The BPFs perform with the worst-case insertion loss of 3.1 dB. Frequency-tuning capable filters operate within 28–38-GHz band. Fractional bandwidth tunability varies from 7.8% to 16.7% at 38 GHz and 7.6% to 12.5% at 28 GHz for the filter that is capable of both tuning mechanisms. The filters are characterized to handle 5 W of the continuous RF power without needing thick ground planes or heat sinks. In addition, the frequency-tuning speed is characterized to be 285 MHz/ms.
more »
« less
Actuation Modeling of a Microfluidically Reconfigurable Radiofrequency Device
Microfluidic-based techniques have been shown to address limitations of reconfigurable radio frequency (RF) antennas and filters in efficiency, power handling capability, cost, and frequency tuning. However, the current devices suffer from significant integration challenges associated with packaging, actuation, and control. Recent advances in reconfigurable microfluidics that utilize the motion of a selectively metalized plate (SMP) for RF tuning have demonstrated promising RF capabilities but have exposed a need for an accurate fluid actuation model. This research presents a model for the mechanical motion of a moving plate in a channel to relate the SMP size, microfluidic channel size, velocity, and inlet pressure. This model facilitates understanding of the actuation response of an RF tuning system based on a moving plate independent of the actuation method. This model is validated using a millimeter-scale plate driven by a gravitational pressure head as a quasi-static pressure source. Measurements of the prototyped device show excellent agreement with the analytical model; thus, the designer can utilize the presented model for designing and optimizing a microfluidic-based reconfigurable RF device and selecting actuation methods to meet desired outcomes. To examine model accuracy at device scale, recent papers in the microfluidics reconfigurable RF area have been studied, and excellent agreement between our proposed model and the literature data is observed.
more »
« less
- Award ID(s):
- 1920953
- PAR ID:
- 10558637
- Publisher / Repository:
- ASME
- Date Published:
- Journal Name:
- Journal of Fluids Engineering
- Volume:
- 146
- Issue:
- 8
- ISSN:
- 0098-2202
- Page Range / eLocation ID:
- 018204
- Subject(s) / Keyword(s):
- electrowetting, microfluidics, dynamic model
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
A microfluidically reconfigurable beamforming network is introduced for beam steering mm-wave antenna arrays. The beamforming network consists of a selectively metallized plate (SMP) that is encapsulated within a microfluidic channel in close proximity to multiple microstrip lines. Metallization traces of the SMP capacitively loads the microstrip lines to realize multiple slow-wave phase shifters. Varying the position of SMP over the lines creates variable phase shifts of the device. Strategically designing the SMP traces on each microstrip line leads to progressive phase shifting, resulting in operation with a single actuator. The manuscript presents a circuit model to facilitate the design of the beamforming network and presents experimental verification with a four-element antenna array operating at 28.5 GHz. The array exhibits continuous beam steering capability within ±30◦ when its SMP is actuated within its -100 to +100 μm displacement range. The beam steering speed from −30◦ to +30◦ is 75 ms. The realized gain is 5.6 dBi at broadside and 6.8 dBi at 30◦ scan angle corresponding to a radiation efficiency of 64% (including all losses in the system). The device is expected to handle 10 W of continuous RF power.more » « less
-
Microfluidics has earned a reputation for providing numerous transformative but disconnected devices and techniques. Active research seeks to address this challenge by integrating microfluidic components, including embedded miniature pumps. However, a significant portion of existing microfluidic integration relies on the time-consuming manual fabrication that introduces device variations. We put forward a framework for solving this disconnect by combining new pumping mechanics and 3D printing to demonstrate several novel, integrated and wirelessly driven microfluidics. First, we characterized the simplicity and performance of printed microfluidics with a minimum feature size of 100 µm. Next, we integrated a microtesla (µTesla) pump to provide non-pulsatile flow with reduced shear stress on beta cells cultured on-chip. Lastly, the integration of radio frequency (RF) device and a hobby-grade brushless motor completed a self-enclosed platform that can be remotely controlled without wires. Our study shows how new physics and 3D printing approaches not only provide better integration but also enable novel cell-based studies to advance microfluidic research.more » « less
-
Hydrodynamic sorting of microchip particles in microchannels is essential in microfluidic systems used for applications requiring particle-based multiplexing. Understanding the forces acting on the particle, as well as the dependencies of the forces on channel and fluid flow parameters, allows for prediction of the flow conditions needed to initiate particle movement, or lift-off. This study presents the experimental characterization of the lift-off of a single, flat-plate, non-neutrally buoyant microchip particle initially sedimented near the inlet of straight, rectangular microfluidic channels of different channel sizes and solvents at moderate Archimedes number of 191 to 2820. The critical shear Reynolds number, corresponding to the minimum required for lift-off, was found to increase with larger Archimedes number and the relationship was found to exhibit particle-channel size dependency. The observed critical lift-off for the flat-plate particle was lower than that predicted using a previous generalized lift-off model based on modified particle Reynolds and Archimedes numbers which may be explained by entrance effects and fluid film lubrication pressure under the particle. Numerical evaluations of the hydrodynamic forces acting on the particle revealed that electrostatic forces are significant. A remodified Archimedes number, based on the channel width, particle diameter, and solvent relative permittivity, is introduced as a correction to the generalized lift-off model to account for hydrodynamics and electrostatics affecting the lift-off of a flat-plate particle. This model is in good agreement with the generalized particle lift-off model and allows for prediction of flat-plate particle lift-off in microfluidic channels for a moderate range of Archimedes numbers.more » « less
-
Abstract Mobile robots with manipulation capability are a key technology that enables flexible robotic interactions, large area covering and remote exploration. This paper presents a novel class of actuation-coordinated mobile parallel robots (ACMPRs) that utilize parallel mechanism configurations and perform hybrid moving and manipulation functions through coordinated wheel actuators. The ACMPRs differ with existing mobile manipulators by their unique combination of the mobile wheel actuators and the parallel mechanism topology through prismatic joint connections. Common motion of the wheels will provide mobile function while their relative motion will actuate the parallel manipulation function. This new concept reduces actuation requirement and increases manipulation accuracy and mobile motion stability through coordinated and connected wheel actuators comparing with existing mobile parallel manipulators. The relative wheel location on the base frame also enables a reconfigurable base size with variable moving stability on the ground. The basic concept and general type synthesis are introduced and followed by kinematics and inverse dynamics analysis of a selected three limb ACMPR. A numerical simulation also illustrates the dynamics model and the motion property of the new mobile parallel robot (MPR) followed by a prototype-based experimental validation. The work provides a basis for introducing this new class of robots for potential applications in surveillance, industrial automation, construction, transportation, human assistance, medical applications, and other operations in extreme environment such as nuclear plants, Mars, etc.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1115/1.4065046
