Nanometer resolution dynamic displacement measurement in industrial/high noise environments

Joseph, Tim John; Kartik, V.

doi:10.1109/icit.2016.7474830

Cited by 4 publications

(6 citation statements)

References 10 publications

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“…The choice of the magnet's material also affects this ratio. A study by these authors on these geometrical aspects was presented in [21], while [20] provided a study on the magnetics involved. dV dR depends upon the excitation applied to the sensor, and increasing the excitation amplitude, as much as allowable, would appear to be the apparent solution.…”

Section: Gmr Sensing Methodsmentioning

confidence: 99%

“…Note that the above resolution is achieved solely by limiting the measurement noise, and no attempt has been made to maximize the sensitivity. A significant increase in the field gradient, and therefore the sensitivity, can be achieved by reducing the sensor-magnet separation [17], [21] and by the use of smaller magnets [20]. The increased sensitivity can directly result in increased resolution, thereby enabling even sub-nanometer resolution.…”

Section: Extrinsic Noise and Experimental Validationmentioning

confidence: 99%

See 1 more Smart Citation

Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing with GMR Sensors

Joseph¹,

Kartik²

2023

Preprint

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<p> Nanometer-resolution position sensing is a critical requirement in several precision applications such as Atomic Force Microscopy (AFM), especially over large bandwidths. Giant magnetoresistance-based (GMR) sen?sors have shown great promise for this; however, they exhibit significantly higher 1/f noise even over large band?widths, which limits the achievable SNR. Therefore, the sensing system needs to be designed at the system-level in order to minimize excess intrinsic noise generation and transmission, as well as external noise pickup. This article, both analytically and experimentally, investigates the noise characteristics of the GMR sensor and its readout circuit components, and their effect on SNR. A general process for designing a low-noise high-bandwidth readout circuit, applicable not just to GMR sensors but also to other high?1/f-noise sensors, is presented. A resolution of 2.5 nm over a bandwidth of 100 kHz is demonstrated on an AFM nanopositioner, a ten-fold improvement over previously reported performance and comparable to other state-of?the-art, but more complex, position sensing schemes. The readout scheme is simple to implement using COTS com?ponents and easily extendable to higher bandwidths, unlike other schemes, such as modulation/demodulation, where the requirement for increasingly higher carrier frequencies renders further improvements in bandwidth impractical. </p>

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Section: Gmr Sensing Methodsmentioning

confidence: 99%

Section: Extrinsic Noise and Experimental Validationmentioning

confidence: 99%

Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing with GMR Sensors

Joseph¹,

Kartik²

2023

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The choice of the magnet's material also affects this ratio. A study by these authors on these geometrical aspects was presented in [23], while [22] provided a study on the magnetics involved. dV dR depends upon the excitation applied to the sensor, and increasing the excitation amplitude, as much as allowable, would appear to be the apparent solution.…”

Section: Gmr Sensing Methodsmentioning

confidence: 99%

“…∆R, and consequently the current source noise, increases with the applied magnetic field bias B. However, over the linear operating region of the sensor, the magnetic gradient dB dx does not vary significantly with B [23]. As a result, the SNR reduces with increasing B and, equivalently, with increasing ∆R.…”

Section: Total (Combined) Noise and Snrmentioning

confidence: 96%

“…The GMR sensing system is deployed in a nanopositioner for an atomic force microscope (AFM), and experiments to validate and benchmark its performance are presented. This article is an extension of our proceedings paper [23]. The remainder of the article is organized as follows: in Section II, the GMR sensing method is detailed; Section III presents component-level noise analysis and design details of the circuit; and experiments to validate the design and demonstrate its performance are presented in Section IV.…”

Section: Introductionmentioning

confidence: 99%

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Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing With GMR Sensors

Joseph

Kartik

2023

IEEE Trans. Instrum. Meas.

Self Cite

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This article presents a low-noise high-bandwidth giant magnetoresistance (GMR) sensor-readout circuit for nanometer resolution position sensing, a critical requirement in several precision applications such as Atomic Force Microscopy (AFM). The main impediment to performance is the GMR sensor's significantly higher 1/f noise extending over large bandwidths, thereby limiting the achievable SNR. Therefore, the sensing system needs to be designed at the system level in order to minimize excess intrinsic noise generation and transmission, as well as external noise pickup. The noise characteristics of the GMR sensor and its readout circuit components, and their effect on SNR, are investigated analytically and experimentally. A general process for designing the readout circuit, applicable not just to GMR sensors but also to other high-1/f-noise sensors, is presented. A resolution of 2.5 nm over a bandwidth of 100 kHz is demonstrated on an AFM nanopositioner, a ten-fold improvement over previously reported GMR sensor performance and comparable to the state-of-the-art, but more complex, capacitive sensors. The readout scheme is simple to implement using COTS components and easily extendable to even higher bandwidths, unlike other schemes, such as modulation/demodulation, where the requirement for increasingly higher carrier frequencies renders further improvements in bandwidth impractical.

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Advances in Capacitive, Eddy Current, and Magnetic Displacement Sensors and Corresponding Interfaces

George

Tan

Nihtianov

2017

IEEE Trans. Ind. Electron.

106

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Nanometer resolution dynamic displacement measurement in industrial/high noise environments

Cited by 4 publications

References 10 publications

Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing with GMR Sensors

Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing with GMR Sensors

Achieving Low-Noise, High-Bandwidth, Nanoscale-Resolution Position Sensing With GMR Sensors

Advances in Capacitive, Eddy Current, and Magnetic Displacement Sensors and Corresponding Interfaces

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