Humidity Sensors with Shielding Electrode Under Interdigitated Electrode

Liu, Hong; Wang, Qi; Sheng, Wenjie; Wang, Xubo; Zhang, Kaidi; Du, Lin; Zhou, Jia

doi:10.3390/s19030659

Cited by 27 publications

(18 citation statements)

References 38 publications

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“…On the other hand, polymer materials have long been used as humidity sensors because of their availability in various forms. In dielectric type humidity sensors, polymer materials such as polyimide [18], polymethyl methacrylate (PMMA) [19], and polyvinyl alcohol (PVA) [20], have been used to bind water molecules between two electrodes such that humidity measurement can be performed through changes in the dielectric constant of the polymer materials.…”

Section: Introductionmentioning

confidence: 99%

The Effect of SnO2 Mixture on a PVA-Based Thick Film Relative Humidity Sensor

Wiranto¹,

Martadi²,

Sulthoni³

et al. 2022

International Journal on Advanced Science, Engineering and Information Technology

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In this research, thick film technology has been used to design and fabricate relative humidity sensors with Polyvinyl Alcohol (PVA) as the sensing layer. The design was optimized to produce an ideal geometry according to the limitations of thick film technology. The sensor fabrication process used screen printing techniques on Alumina (Al2O3) substrate with Silver (Ag) as the electrode material. SnO2 was added to the PVA sensing layer with variations in the composition of 1:1 and 1:2. FTIR analysis showed that the addition of SnO2 did not affect the structure of the PVA, which indicated that there was no chemical reaction between PVA and SnO2. The deposition of the sensing layer was carried out using spin coating method, and the fabricated sensors were then tested by varying 5 humidity points inside a chamber with a hygrometer as a reference. Based on the test results, it was found that the sensors showed responses to humidity variation in the form of changes in resistance values. When the humidity in the chamber increased, the sensor resistance value decreased. The addition of SnO2 could reduce the relatively high resistance value of the PVA-based humidity sensor and also increase the sensor's time response to humidity variation. However, the humidity sensor's sensitivity decreased for the higher composition of SnO2. With this technique, a simple yet stable humidity sensor could be fabricated using thick-film technology with a wide range of potential applications.

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Section: Introductionmentioning

confidence: 99%

The Effect of SnO2 Mixture on a PVA-Based Thick Film Relative Humidity Sensor

Wiranto¹,

Martadi²,

Sulthoni³

et al. 2022

International Journal on Advanced Science, Engineering and Information Technology

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“…Table 1 shows the performance comparison of the fabricated humidity sensor to a previous research work on humidity sensors. Generally, the reported PI-based humidity sensors have two types, capacitive humidity sensor 17,46,58,59 and LC resonance humidity sensor. 24,37 Capacitance-type humidity sensors have high sensitivity and large RH range.…”

Section: Resultsmentioning

confidence: 99%

“…Table shows the performance comparison of the fabricated humidity sensor to a previous research work on humidity sensors. Generally, the reported PI-based humidity sensors have two types, capacitive humidity sensor ,,, and LC resonance humidity sensor. , Capacitance-type humidity sensors have high sensitivity and large RH range. , However, they have issues of power supply and long response and recovery time, which limit their application. In contrast, humidity sensor based on LC resonance has the advantages of noncontact, battery-less, and fast response time, which induces tremendous interest.…”

Section: Resultsmentioning

confidence: 99%

Surface Engineering on Polyimide–Silver Films in Low-Cost, Flexible Humidity Sensors

Luo

Liu

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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In this work, surface engineering is applied to polyimide (PI) films to fabricate low-cost Ag/PI wireless humidity sensors with a resonant frequency of 2.45 GHz. The sensors were obtained by in situ metallization technique coupled with inkjet printing, where PI plays triple roles as a flexible substrate, ion-exchange surface, and sensing material to moisture. Moreover, the humidity sensitivity can be enhanced by the improvement of hydrophilicity via loading with different ions on the PI surface, which has been demonstrated by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The wireless humidity sensor loaded with K+ ions has the maximum sensitivity of 97.7 kHz/% RH at a low relative humidity range of 20–65% and 359.7 kHz/% RH at a high relative humidity of 65–90%, respectively. Accordingly, a sensing mechanism of the fabricated humidity sensor has been discussed in detail. On the other hand, the characteristics of the humidity sensor such as response and recovery speed and stability are analyzed. The mechanical performance tests show that the humidity sensor displays excellent flexibility and good mechanical stability. A strong adhesion between the Ag antenna and PI substrate can be found as well. The passive wireless humidity sensor described in this work has the advantages of having a simple structure, low cost, high sensitivity, long-term stability, and good mechanical properties, which has potential applications in automated industry and healthcare with real-time humidity monitoring.

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“…Relative Humidity (RH) and Air Temperature (T) data recorded during UAV flights are critical parameters to interpret vertical profiles performed with atmospheric sensors, providing information on the Planetary Boundary Layer Height (inversion layer), the altitude of specific atmospheric (dust) layers and clouds in the free troposphere, as well as the influence of water absorption onto ambient aerosols (RH). These measurements are obtained with the HC2-ROPCB sensor (from the Rotronic Company [33]) mounted below the aircraft's wing. A customized 3-D printed probe is housing the sensor to protect it from possible shocks and direct solar irradiance while ensuring proper air flow during flight.…”

Section: Meteorological Sensorsmentioning

confidence: 99%

The Unmanned Systems Research Laboratory (USRL): A New Facility for UAV-Based Atmospheric Observations

et al. 2021

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The Unmanned Systems Research Laboratory (USRL) of the Cyprus Institute is a new mobile exploratory platform of the EU Research Infrastructure Aerosol, Clouds and Trace Gases Research InfraStructure (ACTRIS). USRL offers exclusive Unmanned Aerial Vehicle (UAV)-sensor solutions that can be deployed anywhere in Europe and beyond, e.g., during intensive field campaigns through a transnational access scheme in compliance with the drone regulation set by the European Union Aviation Safety Agency (EASA) for the research, innovation, and training. UAV sensor systems play a growing role in the portfolio of Earth observation systems. They can provide cost-effective, spatial in-situ atmospheric observations which are complementary to stationary observation networks. They also have strong potential for calibrating and validating remote-sensing sensors and retrieval algorithms, mapping close-to-the-ground emission point sources and dispersion plumes, and evaluating the performance of atmospheric models. They can provide unique information relevant to the short- and long-range transport of gas and aerosol pollutants, radiative forcing, cloud properties, emission factors and a variety of atmospheric parameters. Since its establishment in 2015, USRL is participating in major international research projects dedicated to (1) the better understanding of aerosol-cloud interactions, (2) the profiling of aerosol optical properties in different atmospheric environments, (3) the vertical distribution of air pollutants in and above the planetary boundary layer, (4) the validation of Aeolus satellite dust products by utilizing novel UAV-balloon-sensor systems, and (5) the chemical characterization of ship and stack emissions. A comprehensive overview of the new UAV-sensor systems developed by USRL and their field deployments is presented here. This paper aims to illustrate the strong scientific potential of UAV-borne measurements in the atmospheric sciences and the need for their integration in Earth observation networks.

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Humidity Sensors with Shielding Electrode Under Interdigitated Electrode

Cited by 27 publications

References 38 publications

The Effect of SnO2 Mixture on a PVA-Based Thick Film Relative Humidity Sensor

The Effect of SnO2 Mixture on a PVA-Based Thick Film Relative Humidity Sensor

Surface Engineering on Polyimide–Silver Films in Low-Cost, Flexible Humidity Sensors

The Unmanned Systems Research Laboratory (USRL): A New Facility for UAV-Based Atmospheric Observations

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