• Title/Summary/Keyword: Capacitive type sensor

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A CMOS integrated circuit design of charge-sharing scheme for a capacitive fingerprint sensor (용량형 지문인식센서를 위한 전하분할 방식 감지회로의 CMOS 구현)

  • Nam, Jin-Moon;Lee, Moon-Key
    • Journal of Sensor Science and Technology
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    • v.14 no.1
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    • pp.28-32
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    • 2005
  • In this paper, a CMOS integrated detection circuit for capacitive type fingerprint sensor signal processing is described. We designed a detection circuit of charge-sharing sensing scheme. The proposed detection circuit increases the voltage difference between a ridge and valley. The test chip is composed of $160{\times}192$ array sensing cells (12 by $12.7{\;}mm^{2}$). The chip was fabricated on a 0.35 m standard CMOS process. Measured difference voltage between a ridge and valley was 0.95 V.

Implementation of Passive Telemetry RF Sensor System Using Unscented Kalman Filter Algorithm (Unscented Kalman Filter를 이용한 원격 RF 센서 시스템 구현)

  • Kim, Kyung-Yup;Lee, John-Tark
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.10
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    • pp.1861-1868
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    • 2008
  • In this paper, Passive Telemerty RF Sensor System using Unscented Kalman Filter algorithm(UKF) is proposed. General Passive Telemerty RF Sensor System means that it should be "wireless", "implantable" and "batterless". Conventional Passive Telemerty RF Sensor System adopts Integrated Circuit type, but there are defects like complexity of structure and limit of large power consumption in some cases. In order to overcome these kinds of faults, Passive Telemetry RF Sensor System based on inductive coupling principle is proposed in this paper. Because passive components R, L, C have stray parameters in the range of high frequency such as about 200[KHz] used in this paper, Passive Telemetry RF Sensor System considering stray parameters has to be derived for accurate model identification. Proposed Passive Telemetry RF Sensor System is simple because it consists of R, L and C and measures the change of environment like pressure and humidity in the type of capacitive value. This system adopted UKF algorithm for estimation of this capacitive parameter included in nonlinear system like Passive Telemetry RF Sensor System. For the purpose of obtaining learning data pairs for UKF Algorithm, Phase Difference Detector and Amplitude Detector are proposed respectively which make it possible to get amplitude and phase between input and output voltage. Finally, it is verified that capacitive parameter of proposed Passive Telemetry RF Sensor System using UKF algorithm can be estimated in noisy environment efficiently.

An 0.4nm Resolution Encoder-like Capacitive Displacement Sensor (0.4nm 해상도의 엔코더 타입 전기용량형 변위센서)

  • Kang, Dae-Sil;Kim, Moo-Jin;Moon, Won-Kyu
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1450-1454
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    • 2007
  • A Contact-type Linear Encoder-like Capacitive Displacement Sensor (CLECDiS) has been developed to measure displacements at high accuracy within a long measurement range. In this paper, we have worked on improving the performance and reliability of the sensor. The performance increase can be done by introducing the smaller electrode patterns of $4{\mu}m$ width. In order to improve the reliability of the sensor we have changed the electrode layers from chrome-gold to chrome-gold-chrome and re-design its supporting structure. The newly-designed sensor is fabricated and tested to show that its sensitivity is $35pF/{\mu}m$, which implies that its resolution may be 0.36nm if SNR (Signal-to-Noise-Ratio) is 80.1dB. It is about ten times of that $(3.14pF/{\mu}m)$ of its previous version with 10${\mu}m$ electrodes. The total measurement range remains the same as the previous one; 15mm. The calibration experiments show its improved performance and reliability.

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A Study on the Measurement Characteristics of Cylindrical Type Capacitive Transducers to the Roundness Errors of Rotor for Magnetic Bearing (자기베어링용 로우터의 형상 오차에 대한 실린더형 캐패시턴스 센서의 측정특성에 관한 연구)

  • Lee, S.H.;Jung, S.C.;Han, D.C.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.3
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    • pp.23-31
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    • 1995
  • The sending characteristics of the non-contact type displacement transducers can affect the performances of the magnetic bearing systems when they support the rotating shaft. The probe type displacement sensor detects not only the displacement of the rotor at the sensing position but also the surface irregularitis of the rotor such as surface roughnessand roundness errors. If there exist such measuring errors, the magnetic bearing can not apply proper force against the rotor displacements for the detected signal is the input to the magnetic bearing controllers. The cylindrical shape capacitive transducer can detect the rotor displacement by the integral sum of the charges which are formed between the sensor plates and rotor so that it can reduce the detecting errors induced by the surface irregularities of the rotor. By theore- tical analysis, we compared the sensing characteristics of the cylindrical shape capacitive transducers for the rotors that have some sinusoidal irregularities with that of the ideal probe type displacement transducers.

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Evaluation of Diagnosis Properties of Capacitive Sensor about Deteriorated Pattern of Electrical Insulating Oil (전기 절연유의 열화 패턴에 따른 정전용량형 센서의 열화감지특성 평가)

  • Kim, Ju-Han;Kim, Jae-Hoon;Lee, Won-Yeong;Kim, Pil-Hwan;Han, Sang-Ok;Kim, Han-Jun
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1829-1831
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    • 2004
  • This paper described the capacitive sensor for the diagnosis of deterioration of electrical insulating oils applying guard-ring type the 3-terminal electrodes. To measure stable capacitance of the sensor and to determine the design factors of the sensor, we utilized computational analysis, FEM software. This capacitive sensor discern the extent of deterioration measuring relative permittivity of electrical insulating oils. The result of measuring numerous sample, mineral oils, as serviced year, we confirmed an increase in relative permittivity of oils. Moreover, we confirmed the superior characteristics of the sensor as a species, aged pattern of oils and operating temperature.

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Analysis on the Diagnosis Characteristics of Electrical Insulating Oil for Power Transformer with 3-terminal Capacitive Sensor (3전극형 전기용량 센서를 이용한 변압기 절연유의 열화감지특성 평가)

  • Kim, Ju-Han;Seo, Pan-Seok;Kim, Pil-Hwan;Kim, Myung-Hwan;Park, Hung-Seok;Han, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2004.11d
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    • pp.89-92
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    • 2004
  • This paper described the capacitive sensor for the diagnosis of deterioration of electrical insulating oils applying guard-ring type the 3-terminal electrodes. To measure stable capacitance of the sensor and to determine the design factors of the sensor, we utilized computational analysis, FEM software. This capacitive sensor discern the extent of deterioration measuring relative permittivity of electrical insulating oils. The result of measuring numerous sample, mineral oils, as serviced year, we confirmed an increase in relative permittivity of oils. Moreover, we confirmed the superior characteristics of the sensor as a species, aged pattern of oils and operating temperature.

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Fabrication of Relative-type Capacitive Pressure Sensor (상대압 용량성 압력센서의 제작)

  • 서희돈;임근배;최세곤
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.7
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    • pp.82-88
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    • 1993
  • This paper describes fabrication of relative type capacitive pressure sensor to be in great demand for many fields. The fabricated sensor consists of two parts` a sensing diaphragm and a pyrox glass cover. The sensor size is 4.5${\times}3.4mm$^{2})$ and 400$\mu$m thick. To improve the nonlinearity, this sensor is designed a rectangular silicon diaphragm with a center boss structure, and in order to improve the temperature characteristics of the sensor in a packaging process, the sensing element is mounted on the pyrex glass support. Some suggestions toward the design and fabrication of improved sensors have been presented. The zero pressure capacitance, Co of sensor is 26.57pF, and the change of capacitance, ${\Delta}$C is 1.55pF from 0Kgf/Cm$^{2}$ to 1Kgf/Cm$^{2}$ at room temperature. The nonlinearity of the sensor output with center boss diaphragm is 1.29%F.S., and thermal zero shift and thermal sensitivity shift is less than 1.43%F.S./$^{\circ}C$and 0.14% F.S./$^{\circ}C$, respectively.

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Development and Evaluation of 3-terminal Type Capacitive Sensor for the Diagnosis of Electrical Insulating Oil (전기 절연유 열화진단을 위한 3-단자식 전기용량 센서 개발 및 진단특성 평가)

  • Kim, Ju-Han;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.4
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    • pp.476-482
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    • 2009
  • This paper describes the development of capacitive sensor for the diagnosis of liquid dielectrics, which is widely used as the electrical insulating oil of transformer, circuit breaker, cable and etc. To survey the dielectric properties of the virgin and aged electrical insulating oils, we utilized the highly precise measuring system, using the principle of cross capacitance. The measured properties were used to determine the design factors of the sensor. Then the factors were optimized with the help of computational analysis. To evaluate diagnosis by the sensor, we performed accelerated thermal aging test about electrical insulating oils. The condition of aged specimens were investigated by measurements of relative permittivity i.e. capacitance change by capacitive sensor. And to evaluate the hysteresis characteristics with the change of temperature, we constructed a testing system, which was composed with vacuum drying oven, oil chamber and measuring instruments, such as LCR meter, MUX and so forth. Through the results of this investigation, we confirmed the superior characteristics of the newly developed sensor.

Optimum Design of 3-Axis Sensor System for Vibration Measurement Using Piezoresistive type MEMS Sensor (압전저항형 멤스센서를 이용한 진동 측정용 3축 센서 시스템의 최적화 설계)

  • Seo, Sang-Yoon;Bae, Dong-Myung;Lee, Jong-Kyu;Choi, Byeong-Keun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.12
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    • pp.1082-1089
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    • 2013
  • 3-Axis sensor measurement system is needed for measuring ride quality of elevator. But because 3-Axis piezoelectric accelerometer is expensive. We developed 3-Axis sensor system which is suitable for measuring ride quality of elevator using cheap MEMS sensor. There are two types of MEMS sensor that are piezoresistive and capacitive type. The excellence of piezoresistive type in characteristic of frequency response and noise is confirmed compare to capacitive type as a result of this paper's experiment and reference. 3-Axis system using MEMS sensor needs MEMS's proper frequency response characteristic. Additionally noise characteristic of sensor and circuit, stiffness of assembly are needed for deciding frequency range and accuracy of amplitude.