Wireless Readout of Passive <i>LC</i> Sensors

Nopper, R. W.; Niekrawietz, Remigius; Reindl, Leonhard M.

doi:10.1109/tim.2009.2032966

Cited by 149 publications

(95 citation statements)

References 11 publications

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“…The sensor exhibits reduced sensitivity at pressures beyond 100 mm Hg. This behaviour is similar to the capacitive pressure sensor-based microstructured rubber we previously reported, and the origin was also previously discussed 28 . In the linear region, we can use the simple expression below to translate peak frequency measurements f 0 into physical pressure values P (f 0 ),…”

Section: Resultssupporting

confidence: 90%

“…However, with all the sensors operating below a few hundred MHz, none has been able to miniaturize below a few mm 3 in volume [3][4][5][6][7][8][9][10][22][23][24][25][26] . Traditional passive strategies have been inherently limited by the self-resonant frequency of readout circuitry because interference effects make it difficult to detect sensors operating near and above this frequency [27][28][29] .…”

mentioning

confidence: 99%

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Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care

et al. 2014

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Continuous monitoring of internal physiological parameters is essential for critical care patients, but currently can only be practically achieved via tethered solutions. Here we report a wireless, real-time pressure monitoring system with passive, flexible, millimetre-scale sensors, scaled down to unprecedented dimensions of 1 Â 1 Â 0.1 cubic millimeters. This level of dimensional scaling is enabled by novel sensor design and detection schemes, which overcome the operating frequency limits of traditional strategies and exhibit insensitivity to lossy tissue environments. We demonstrate the use of this system to capture human pulse waveforms wirelessly in real time as well as to monitor in vivo intracranial pressure continuously in proof-of-concept mice studies using sensors down to 2.5 Â 2.5 Â 0.1 cubic millimeters. We further introduce printable wireless sensor arrays and show their use in real-time spatial pressure mapping. Looking forward, this technology has broader applications in continuous wireless monitoring of multiple physiological parameters for biomedical research and patient care.

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Section: Resultssupporting

confidence: 90%

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confidence: 99%

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care

et al. 2014

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“…When the signal frequency is equal to the sample resonant frequency, the input impedance of the reader antenna will clearly change. 12 The sample resonant frequency can be obtained through monitoring the antenna impedance phase as a function of frequency.…”

Section: Measurement Methodsmentioning

confidence: 99%

Measurement of relative permittivity of LTCC ceramic at different temperatures

Tan

Hao

et al. 2014

AIP Advances

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Devices based on LTCC (low-temperature co-fired ceramic) technology are more widely applied in high temperature environments, and the temperature-dependent properties of the LTCC material play an important role in measurements of the characteristics of these devices at high temperature. In this paper, the temperature-dependence of the relative permittivity of DuPont 951 LTCC ceramic is studied from room temperature to 500 °C. An expression for relative permittivity is obtained, which relates the relative permittivity to the resonant frequency, inductance, parasitic capacitance and electrode capacitance of the LTCC sample. Of these properties, the electrode capacitance is the most strongly temperature-dependent. The LTCC sample resonant frequency, inductance and parasitic capacitance were measured (from room temperature to 500 °C) with a high temperature measurement system comprising a muffle furnace and network analyzer. We found that the resonant frequency reduced and the inductance and parasitic capacitance increased slightly as the temperature increases. The relative permittivity can be calculated from experimental frequency, inductance and parasitic capacitance measurements. Calculating results show that the relative permittivity of DuPont 951 LTCC ceramic ceramic increases to 8.21 from room temperature to 500 °C.

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“…(12,13) To take measurements, the reader antenna sends an alternating electromagnetic signal to the sensor inductance coils. If the signal frequency is equal to the sensor resonance frequency, the input impedance of the antenna clearly changes, (14) allowing for the determination of the sensor resonant frequency by measuring antenna impedance characteristics such as phase with an impedance analyzer.…”

Section: Designmentioning

confidence: 99%

Zirconia Ceramics Applied in a Pressure-Sensitive Device Fabricated Using HTCC Technology

2014

Sensors and Materials

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A wireless passive high-temperature cofired ceramic (HTCC) pressure sensor fabricated from partially stabilized zirconia (PSZ) ceramic is proposed. This sensor can be used in high-temperature environments (in excess of 1000 °C in some cases) owing to its high mechanical strength at high thermal stress, and pressure data can be transmitted through mutual inductance coupling. Experimental systems are designed to obtain the necessary frequency-pressure and frequency-temperature characteristics. The experimental results between room temperature and 800 °C (and then at 800 °C for 30 min) indicate that the sensor has improved stability at 800 °C and the sensor also shows a high sensitivity at room temperature.

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Wireless Readout of Passive LC Sensors

Cited by 149 publications

References 11 publications

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care

Continuous wireless pressure monitoring and mapping with ultra-small passive sensors for health monitoring and critical care

Measurement of relative permittivity of LTCC ceramic at different temperatures

Zirconia Ceramics Applied in a Pressure-Sensitive Device Fabricated Using HTCC Technology

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