Low-cost wireless corrosion and conductivity sensors

Andringa, Matthew M.; Puryear, John M.; Neikirk, Dean P.; Wood, Sharon L.

doi:10.1117/12.658836

Cited by 8 publications

(8 citation statements)

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“…7, may contribute to this error. A pseudo Q fitting algorithm (Andringa et al 2006) is used to extract quality factor of the sensor. The results are compared to calculated Q based on measured resonance, estimated L (0.266 lH) and R (5.9 X) from Eq.…”

Section: Discussionmentioning

confidence: 99%

Microfabricated self-resonant structure as a passive wireless dielectric constant and conductivity sensor

2011

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This paper describes a low cost, passive wireless dielectric constant and conductivity sensor using a microfabricated inductor with interdigitated capacitors (IDC). A self-resonant-structure (SRS) is designed by incorporating IDC electrodes in the inter-winding space of the inductor. The distributed capacitance and conductance of the sensor is affected by dielectric constant (e) and conductivity (r) of its environment or material under test (MUT). The e and r can be used to provide information about the surrounding environment. This serves as an impedance transducer changing the resonant frequency and phase dip of the SRS. The SRS is interrogated using a noncontact inductively coupled reader coil. The change in resonance frequency and phase dip of the SRS is used to detect material properties of the environment/MUT. The relationship between sensor layout and coupling factor between sensor and reader is investigated. Optimizations of the coupling factor based on this relationship are discussed. IDC design trade-offs between the sensor's sensitivity and coupling factor are also investigated. The sensor's response to variety of liquid MUTs with a wide range of dielectric constant and conductivity is presented.

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Section: Discussionmentioning

confidence: 99%

Microfabricated self-resonant structure as a passive wireless dielectric constant and conductivity sensor

2011

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“…We have also been investigating approaches that would facilitate remotely-read detectors for chemical vapors by extending our work on single resonant rf (radio frequency) tags that have already demonstrated the ability to sense a variety of conditions [13][14][15]. These sensors are interrogated in a non-contact manner and rely on resonance to transmit information about the state of tag.…”

Section: Wireless Resonant Chemical Sensorsmentioning

confidence: 97%

“…These devices are wirelessly interrogated using a wide range of radio frequencies, depending on the specific design of the tag. We have already developed a system using resonant tags for structural health monitoring of steel reinforced concrete, including the non-contact measurement of conductivity and corrosion in concrete [13][14][15]. Although the wireless scheme was devised to meet the constraints of civil engineering applications, a similar approach should be useful for micro-total analytical systems (µTAS) by allowing the integration of many microfluidic components in a manner that does not interfere with electrical or optical access to the actual transducer.…”

Section: Wireless Resonant Chemical Sensorsmentioning

confidence: 99%

Resonant chemical surveillance tags

2007

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Results will be reported from efforts to develop a self-contained micromachined microfluidic detection system for the presence of specific target analytes under the US Office of Naval Research CIED Basic Research Program. Our efforts emphasize improving/optimizing a dedicated micromachined sensor array with integrated photodetectors that are coupled to chemically sensitized chemiluminescent receptors. Here we will review our work on the fabrication of integrated photodiodes within an array of micromachined silicon pyramidal cavities that will contain the chemiluminescent compounds. One particular advantage of such approach over a conventional planar photodiode would be its collection efficiency without the use of external optical components. This should allow a more compact and robust system to be constructed by integrating photodetection and fluidics into a single chip-based platform. Additionally, overview of accessing the photodiode using wireless coupling to a resonant chemically sensitive tag will be discussed.

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“…However, SAW sensors suffer from high losses [SAW losses] and it can be difficult to efficiently couple the measurand to the surface acoustic waves within the sensor [6,7]. Magneto-resonant [8,9] and resonant coil based systems are other methods for measurement of a large number of physical parameters [10,11]. These sensors have proven useful for measuring corrosion [11].…”

Section: Introductionmentioning

confidence: 99%

“…Magneto-resonant [8,9] and resonant coil based systems are other methods for measurement of a large number of physical parameters [10,11]. These sensors have proven useful for measuring corrosion [11].…”

Section: Introductionmentioning

confidence: 99%

RF Cavity Passive Wireless Sensors With Time-Domain Gating-Based Interrogation for SHM of Civil Structures

2009

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Many existing sensing technologies for application to the monitoring of large systems or civil structures have a serious deficiency in that they require some type of wired physical connection to the outside world. This causes significant problems in the installation and long term use of these sensors. This paper describes a new type of passive wireless sensor that is based on resonant RF cavities, where the resonant frequency is modulated by a measurand. In the case of a strain sensor, the electrical length of the cavity directly modulates it's resonant frequency. A probe inside the cavity couples RF signals from the cavity to an externally attached antenna. The sensor can then be interrogated remotely using microwave pulse-echo techniques. Such a system has the advantage of requiring no permanent physical connection between the sensor and the data acquisition system. In this type of sensor the RF interrogation signal is transmitted to the sensor and then re-radiated back to the interrogator from the sensor resulting in a signal strength that decreases with the forth power of distance. This places an upper limit on the distance over which the sensor can be interrogated. Theoretical estimates show that these sensors can be interrogated with sufficient signal-to-noise ratio at distances exceeding 10 m for radiated powers of less than 1 mW. We present results for a strain sensor and a displacement sensor that can be interrogated at a distance of 8 m with a strain resolution of less than 10 ppm and displacement resolution of 0.01 mm, respectively.

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Low-cost wireless corrosion and conductivity sensors

Cited by 8 publications

References 0 publications

Microfabricated self-resonant structure as a passive wireless dielectric constant and conductivity sensor

Microfabricated self-resonant structure as a passive wireless dielectric constant and conductivity sensor

Resonant chemical surveillance tags

RF Cavity Passive Wireless Sensors With Time-Domain Gating-Based Interrogation for SHM of Civil Structures

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