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.
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This content will become publicly available on August 1, 2025
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.
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- 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
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