A micromachined airflow sensor based on RF evanescent-mode cavity resonator

Zhao, Yirong; Kim, Seong-Hyok; Li, Yuan; Pan, Bo; Wu, Xiaosong; Tentzeris, Manos M.; Parapolymerou, John; Allen, Mark G.

doi:10.1109/mwsym.2008.4633273

Cited by 6 publications

(1 citation statement)

References 12 publications

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“…These sensors measure the amplitude of physical quantities, and hence, their performance is directly affected by the magnitude of noise and signal drift. On the other hand, resonant sensors that measure resonant frequency changes or phase changes are relatively robust against noise levels and signal drift [8,9]. Conventional resonant flow sensors consist of excitation and detection parts [10].…”

Section: Introductionmentioning

confidence: 99%

A self-resonant micro flow velocity sensor based on a resonant frequency shift by flow-induced vibration

Seo¹,

Kim²

2010

J. Micromech. Microeng.

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We report the development of a self-resonant flow sensor based on a resonant frequency shift due to flow-induced vibrations. The vibration of a microcantilever beam, induced by a turbulent flow, is modulated with its own natural frequency, and the resonant frequency is shifted by a surface stress on the beam due to fluid drag force. The vibration induced by air flow is measured by using a piezoelectric PZT material on a silicon cantilever beam. The theoretical resonant frequencies of two cantilever beams (lengths: 610 μm and 2000 μm) are 12416 Hz and 1155 Hz, respectively. For the air flow velocities of 2.8 m s −1 and 9.7 m s −1 , the shifted resonant frequencies of the cantilever beam whose length is 610 μm are 12 810 Hz and 15 602 Hz, respectively. Sensitivities of the two self-resonant flow sensors with the 610 and 2000 μm long beams are approximately 384 ± 15 Hz/(m/s) and 20.4 ± 0.6 Hz/(m/s), respectively.

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Section: Introductionmentioning

confidence: 99%

A self-resonant micro flow velocity sensor based on a resonant frequency shift by flow-induced vibration

Seo¹,

Kim²

2010

J. Micromech. Microeng.

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Passive Chipless RFID Sensors: Concept to Applications—A Review

Patre

2022

IEEE J. Radio Freq. Identif.

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The open-ended waveguide transducer with wire in circular window

Grymalyuk

Drobakhin

2013

2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves

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Development of microwave scanning near-field microscopy and introscopy in millimeter-wave range is the problem of keen interest [1][2][3][4] due to perspectives of applications in novel technologies. The detection of defects in dielectric slabs and measurements of parameters of materials are urgent tasks of the applied physics. A method of employing waveguide-type microscopic aperture probe has been proposed in [1]. It has been shown that the microscopic aperture has allowed one to get high spatial resolution of scanning microscopy for surface topography. Structures consisting with a conducting plate, placed outside a waveguide-fed rectangular aperture were proposed for non-destructive measurements of the dielectric samples [2,3]. Specifically, λ/4 -resonator and ring microwave one can be used for this purpose as an initial transducer. But the problem is to improve the spatial resolution and sensitivity. The advantage of waveguide structures is excellent shielding effect due to its metallic walls, thus avoiding radiation loss even in the millimeter-wave range. Thus, creation of the sensors in millimeter range on the basis of the waveguide structures is rather perspective. Earlier it was considered many approaches of establishing the various sensors. For example, a radio-frequency evanescent-mode cavity resonator for passive wireless sensor applications has been presented in [5,6]. These papers considered such structures for the various airflow measurements. The purpose of this paper is investigation of a novel structure of an initial transducer on the base of ideas of [5,6].The structure of proposed insertion is shown in Fig. 1 (a). Its cross-section dimensions of the waveguide were of 7.2×3.4 mm. Circular window diameter was of 2 mm, the diameter of the wire was of 0.6 mm. The dielectric layer placed right against the insertion flange is presented in Fig. 1 (b). a) b) Figure 1. The structure of the insertion with wire in circular window (a) and the longitudinal section of structure with dielectric layer placed right against the insertion flange (b)The material of the waveguide insertion was copper. The dielectric layer with loss angle tangent of 0.001 had sizes of 7.2×3.4×1 mm. The calculations were carried out by the finite element method. The reflection coefficient (R) versus frequency for the suggested insertion with the dielectric layer has shown in Fig. 2. The dielectric permittivity of the slab was varied from 4 to 7. The graphs of the reflection coefficient has been presented only for some selected values of the permittivity in order to present the behavior of two different resonance frequencies which have been induced by different properties of the structure. The resonance curve 442 978-1-4799-1068-7/13/$31.00 ©2013 IEEE

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A micromachined airflow sensor based on RF evanescent-mode cavity resonator

Cited by 6 publications

References 12 publications

A self-resonant micro flow velocity sensor based on a resonant frequency shift by flow-induced vibration

A self-resonant micro flow velocity sensor based on a resonant frequency shift by flow-induced vibration

Passive Chipless RFID Sensors: Concept to Applications—A Review

The open-ended waveguide transducer with wire in circular window

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