High sensitivity CMOS humidity sensors with on-chip absolute capacitance measurement system

Boltshauser, T.; Leme, C.A.; Baltes, H.

doi:10.1016/0925-4005(93)85030-e

Cited by 47 publications

(23 citation statements)

References 4 publications

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“…Furthermore, this kind of devices can be manufactured without requiring micromachining but directly by using deposition of a layer on a substrate and, therefore, they are compatible with any kind of technology. Some authors have analysed the influence of geometry of this kind of structures in the sensor performance [5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of printed capacitive sensors

Rivadeneyra

Salmerón

Palma

et al. 2015

2015 10th Spanish Conference on Electron Devices (CDE)

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This paper presents a comparative study of four planar capacitive sensors with different geometrical layouts. These sensors have been fabricated by inkjet printing on a flexible substrate whose electrical permittivity is dependent on relative humidity. We have used numerical simulations to design each of these structures. In particular, we present the calibration curves of interdigitated electrodes, meandered electrodes, spiral electrodes, and serpentine electrodes in terms of relative humidity. Although the selection of the best configuration will depend on the specific application and its requirements, in terms of sensitivity within the same sensing area the lowest value is achieved by meandered electrodes, followed by interdigitated, spiral, and serpentine electrodes, in this order.

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Section: Introductionmentioning

confidence: 99%

Comparative study of printed capacitive sensors

Rivadeneyra

Salmerón

Palma

et al. 2015

2015 10th Spanish Conference on Electron Devices (CDE)

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“…However, they fail to function properly when there is water condensation at high RH levels. The problem of capacitive sensors can be solved by adopting thermal conductivity-based sensors [1], [4]- [5].…”

Section: Introductionmentioning

confidence: 99%

A low-power switched-capacitor humidity sensor interface

Shuqin

Chan

2010

2010 IEEE Asia Pacific Conference on Circuits and Systems

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In this paper, a new switched-capacitor (SC) interface circuit for humidity sensor application is proposed. The sensing principle makes use of the difference between the thermal conductivity of air and water vapor at elevated temperatures. It causes a voltage difference between two isolated diodes. The reference diode is sealed and has a fixed thermal conductance, while the sensing diode is exposed to the environment having a humidity-dependent thermal conductance. The exposed diode is connected to the proposed SC circuit, which can be easily monolithically integrated using GlobalFoundries 0.18-µm CMOS process. The simulation results show that the humidity sensitivity of the sensor is 6.84, 12.44, 22.51mV/%RH for 20ºC, 30ºC and 40ºC respectively. The key advantage is that the circuit operates across the full range of humidity levels for environment temperatures from 20ºC to 40ºC. The humidity sensing interface operates under a supply voltage of 3V and dissipates power as low as 400µW including the biasing circuits.

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“…Capacitive detection method is a widely used technique to measure relative humidity(RH) [1][2][3][4][5][6][7][8]. Generally, capacitive humidity sensors are comprised of a pair of electrodes and a humidity-sensitive insulating layer, made from materials such as polymer [9][10][11][12], metal oxide [13,14], and semiconductors [15,16].…”

Section: Introductionmentioning

confidence: 99%

A Simple Capacitive Sensor Array Based on a Metal-Insulator-Metal Structure

Lee¹,

Choi²,

Ahn³

et al. 2012

Journal of Sensor Science and Technology

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A simple array of metal-insulator-metal capacitive elements was proposed for a potential application in humidity sensing platforms. We fabricated meso-scale sensors with different sizes(large-size: 2.7 x 2.7 mm 2 ; mid-size: 1.5 x 1.5 mm 2 ; small-size: 0.7 x 0.7 mm 2 ) and characterized the performance of each design. Polyimide films were utilized as a humidity-sensitive layer. Capacitance changes of the polyimide layer were measured with respect to water absorption. The device showed sensitivity in the full range of relative humidity (RH) with excellent linearity(correlation coefficient > 0.994). This array structure exhibits unique advantages including easy fabrication process, high batch productivity, and high structural compatibility with various substrate materials. It is anticipated that this device structure will be potentially useful in unique applications including mapping spatial humidity variations over a meso-scale area and implementing flexible humidity sensing element arrays.

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High sensitivity CMOS humidity sensors with on-chip absolute capacitance measurement system

Cited by 47 publications

References 4 publications

Comparative study of printed capacitive sensors

Comparative study of printed capacitive sensors

A low-power switched-capacitor humidity sensor interface

A Simple Capacitive Sensor Array Based on a Metal-Insulator-Metal Structure

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