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Anthony J. Hanson

Bio: Anthony J. Hanson is an academic researcher from Western Michigan University. The author has contributed to research in topics: Relative humidity & Microstrip antenna. The author has an hindex of 5, co-authored 11 publications receiving 64 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a novel porous polydimethylsiloxane (PDMS)-based capacitive pressure sensor was fabricated by optimizing the dielectric layer porosity for wide-range pressure sensing applications in the sports field.
Abstract: A novel porous polydimethylsiloxane (PDMS)-based capacitive pressure sensor was fabricated by optimizing the dielectric layer porosity for wide-range pressure sensing applications in the sports field. The pressure sensor consists of a porous PDMS dielectric layer and two fabric-based conductive electrodes. The porous PDMS dielectric layer was fabricated by introducing nitric acid (HNO3) into a mixture of PDMS and sodium hydrogen bicarbonate (NaHCO3) to facilitate the liberation of carbon dioxide (CO2) gas, which induces the creation of porous microstructures within the PDMS dielectric layer. Nine different pressure sensors (PS1, PS2,..., PS9) were fabricated in which the porosity (pore size, thickness) and dielectric constant of the PDMS dielectric layers were varied by changing the curing temperature, the mixing proportions of the HNO3/PDMS concentration, and the PDMS mixing ratio. The response of the fabricated pressure sensors was investigated for the applied pressures ranging from 0 to 1000 kPa. A relative capacitance change of ∼100, ∼323, and ∼485% was obtained by increasing the curing temperature from 110 to 140 to 170 °C, respectively. Similarly, a relative capacitance change of ∼170, ∼282, and ∼323% was obtained by increasing the HNO3/PDMS concentration from 10 to 15 to 20%, respectively. In addition, a relative capacitance change of ∼94, ∼323, and ∼460% was obtained by increasing the PDMS elastomer base/curing agent ratio from 5:1 to 10:1 to 15:1, respectively. PS9 exhibited the highest sensitivity over a wide pressure sensing range (low-pressure ranges (<50 Pa), 0.3 kPa-1; high-pressure ranges (0.2-1 MPa), 3.2 MPa-1). From the results, it was observed that the pressure sensors with dielectric layers prepared at relatively higher curing temperatures, higher HNO3 concentrations, and higher PDMS ratios resulted in increased porosity and provided the highest sensitivity. As an application demonstrator, a wearable fit cap was developed using an array of 16 pressure sensors for measuring and mapping the applied pressures on a player's head while wearing a helmet. The pressure mapping aids in observing and understanding the proper fit of the helmet in sports applications.

74 citations

Journal ArticleDOI
TL;DR: In this article, a tunable and compact microstrip antenna for industrial, scientific and medical (ISM) band applications is presented, with an overall dimension of $65\times 46\times 0.127$ mm, fabricated by sandwiching a flexible Kapton polyimide substrate, with a dielectric constant of 3.5, between two flexible copper tapes, as the radiating patch and ground plane.
Abstract: Design and rapid prototyping of a tunable and compact microstrip antenna for industrial, scientific and medical (ISM) band applications is presented in this paper. Laser machining is introduced as a fast and accurate method for the antenna fabrication. The antenna, with an overall dimension of $65\times 46\times0.127$ mm, was fabricated by sandwiching a flexible Kapton polyimide substrate, with a dielectric constant of 3.5, between two flexible copper tapes, as the radiating patch and ground plane, respectively. The radiating patch was patterned in a meander configuration, with three slots, demonstrating the capability to reduce the resonant frequency of the microstrip antenna from 2.4 GHz to 900 MHz, without increasing the overall size of the antenna (87% compact). The effect of mechanical stress on the antenna performance was investigated by performing bend and stretch tests. The antenna was subjected to compressive bend with a minimum radius of curvature of 86 mm and 150 mm along the x-axis and y-axis which resulted in a maximum increase of resonant frequency by 3.1% and 1.3%, respectively. Similarly, the antenna was subjected to tensile bend with a minimum radius of curvature of 79 mm and 162 mm along the x-axis and y-axis which resulted in a maximum decrease of the resonant frequency by 4.2% and 0.3%, respectively. An overall 0.9% decrease in the resonant frequency was measured for an applied strain of 0.09% during stretching the antenna along the y-axis.

27 citations

Proceedings ArticleDOI
01 Oct 2019
TL;DR: In this paper, a novel porous polydimethylsiloxane (PDMS) capacitive pressure sensor was fabricated on a fabric platform using additive screen printing process and measured the capacitive response of the pressure sensor for varying pressures ranging from 0 to 900 kPa.
Abstract: A novel porous polydimethylsiloxane (PDMS) capacitive pressure sensor was fabricated on a fabric platform using additive screen printing process. The porous PDMS was prepared using a mixture of PDMS, sodium hydrogen bicarbonate (NaHCO3) and nitric acid (HNO3) and implemented as a dielectric layer. The fabric based top and bottom electrodes were developed by screen printing silver (Ag) ink on thermoplastic polyurethane (TPU) and permanently attaching it on to a fabric using heat lamination process. The capacitive response of the pressure sensor was recorded for varying pressures ranging from 0 to 900 kPa. A relative capacitance change of ~10%, ~180% and ~300% was obtained for the applied pressure ranges of 0 to 20 kPa, 50 to 200 kPa and 300 to 900 kPa, respectively. The detailed fabrication process of the pressure sensor as well as its capacitive response is analyzed and reported in this paper.

25 citations

Proceedings ArticleDOI
08 Jul 2019
TL;DR: In this paper, a resistive flexible humidity sensor based on carbon nanotubes (CNT) was designed and fabricated, and the capability of the printed sensor was investigated by subjecting it to relative humidity (RH) ranging from 30% to 60%.
Abstract: A resistive flexible humidity sensor based on carbon nanotubes (CNT) was designed and fabricated. Screen and gravure printing processes were used for the fabrication of the humidity sensor containing interdigitated electrodes (IDE), a sensing layer and a meandering conductive heater. The capability of the printed sensor was investigated by subjecting it to relative humidity (RH) ranging from 30% to 60%. This response demonstrated an overall resistance change of ~29% when the sensor was subjected to 60% RH, when compared to 30% RH. A maximum hysteresis of ~5.8%, at 40% RH, was calculated for the resistive response of the sensor. The fabrication method and sensor response are analysed and presented in this paper.

21 citations

Proceedings ArticleDOI
08 Jul 2019
TL;DR: In this paper, a fluorinated graphene-based humidity sensor was successfully developed for humidity monitoring applications, which was fabricated by screen printing silver interdigitated electrodes (IDEs) on a flexible polyimide substrate.
Abstract: A novel fluorinated graphene-based humidity sensor was successfully developed for humidity monitoring applications. The humidity sensor was fabricated by screen printing silver (Ag) interdigitated electrodes (IDEs) on a flexible polyimide substrate. A fluorinated graphene powder, that was uniformly dispersed in isopropyl alcohol (IPA) using the ultra-sonication process, was drop casted on the IDEs as a humidity sensing layer. The resistive response of the fabricated humidity sensor towards varying relative humidity (RH) levels ranging from 20% RH to 70% RH, in steps of 10% RH, was investigated at a constant temperature of 24 °C. A maximum resistance change of 12.1% was observed when the humidity was changed from 20% RH to 70% RH, with a sensitivity of 0.24 %/%RH.

14 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a hierarchical porous structured polydimethylsiloxane (PDMS) composites with a simple and cost-effective method using sugar particles and a water-in-oil emulsion were employed as the dielectric layers of flexible capacitive pressure sensors.
Abstract: Pressure sensors for wearable electronics are mounted on irregular surfaces and exposed to various external stimuli. Therefore, the sensor should have a flexible structure and wide pressure measurement range along with high sensitivity. In this study, we fabricated hierarchically porous structured polydimethylsiloxane (PDMS) composites with a simple and cost-effective method using sugar particles and a water-in-oil emulsion. Hierarchically porous PDMS composites were employed as the dielectric layers of flexible capacitive pressure sensors. The capacitive pressure sensor presents a sensitivity 22.5 times higher (0.18 kPa−1) than the sensors using bulk PDMS with a wide measurement range (0–400 kPa). The finite element analysis was implemented to analyze the non-linearity of sensors by observing the compressive behavior of the PDMS composites. For the practical applications, finger attached-sensor, respiration monitoring system, and sensor array were tested, and the proposed sensors showed sufficient potential for application in wearable electronics.

128 citations

Journal ArticleDOI
TL;DR: The need for flexible antennas, materials, and processes used for fabricating the antennas, various material properties influencing antenna performance, and specific biomedical applications accompanied by the design considerations are focused on.
Abstract: The field of flexible antennas is witnessing an exponential growth due to the demand for wearable devices, Internet of Things (IoT) framework, point of care devices, personalized medicine platform, 5G technology, wireless sensor networks, and communication devices with a smaller form factor to name a few. The choice of non-rigid antennas is application specific and depends on the type of substrate, materials used, processing techniques, antenna performance, and the surrounding environment. There are numerous design innovations, new materials and material properties, intriguing fabrication methods, and niche applications. This review article focuses on the need for flexible antennas, materials, and processes used for fabricating the antennas, various material properties influencing antenna performance, and specific biomedical applications accompanied by the design considerations. After a comprehensive treatment of the above-mentioned topics, the article will focus on inherent challenges and future prospects of flexible antennas. Finally, an insight into the application of flexible antenna on future wireless solutions is discussed.

101 citations

Journal ArticleDOI
TL;DR: In this paper, a novel porous polydimethylsiloxane (PDMS)-based capacitive pressure sensor was fabricated by optimizing the dielectric layer porosity for wide-range pressure sensing applications in the sports field.
Abstract: A novel porous polydimethylsiloxane (PDMS)-based capacitive pressure sensor was fabricated by optimizing the dielectric layer porosity for wide-range pressure sensing applications in the sports field. The pressure sensor consists of a porous PDMS dielectric layer and two fabric-based conductive electrodes. The porous PDMS dielectric layer was fabricated by introducing nitric acid (HNO3) into a mixture of PDMS and sodium hydrogen bicarbonate (NaHCO3) to facilitate the liberation of carbon dioxide (CO2) gas, which induces the creation of porous microstructures within the PDMS dielectric layer. Nine different pressure sensors (PS1, PS2,..., PS9) were fabricated in which the porosity (pore size, thickness) and dielectric constant of the PDMS dielectric layers were varied by changing the curing temperature, the mixing proportions of the HNO3/PDMS concentration, and the PDMS mixing ratio. The response of the fabricated pressure sensors was investigated for the applied pressures ranging from 0 to 1000 kPa. A relative capacitance change of ∼100, ∼323, and ∼485% was obtained by increasing the curing temperature from 110 to 140 to 170 °C, respectively. Similarly, a relative capacitance change of ∼170, ∼282, and ∼323% was obtained by increasing the HNO3/PDMS concentration from 10 to 15 to 20%, respectively. In addition, a relative capacitance change of ∼94, ∼323, and ∼460% was obtained by increasing the PDMS elastomer base/curing agent ratio from 5:1 to 10:1 to 15:1, respectively. PS9 exhibited the highest sensitivity over a wide pressure sensing range (low-pressure ranges (<50 Pa), 0.3 kPa-1; high-pressure ranges (0.2-1 MPa), 3.2 MPa-1). From the results, it was observed that the pressure sensors with dielectric layers prepared at relatively higher curing temperatures, higher HNO3 concentrations, and higher PDMS ratios resulted in increased porosity and provided the highest sensitivity. As an application demonstrator, a wearable fit cap was developed using an array of 16 pressure sensors for measuring and mapping the applied pressures on a player's head while wearing a helmet. The pressure mapping aids in observing and understanding the proper fit of the helmet in sports applications.

74 citations

Journal ArticleDOI
TL;DR: In this paper, a resistive flexible humidity sensor based on multi-walled carbon nanotubes (MWCNTs) was designed and fabricated, and the capability of the printed sensor, with heater, was investigated by subjecting it to relative humidity (RH) ranging from 10% to 90%.
Abstract: A resistive flexible humidity sensor based on multi-walled carbon nanotubes (MWCNTs) was designed and fabricated. Screen and gravure printing processes were used for monolithically fabricating the humidity sensor containing interdigitated electrodes (IDE), a sensing layer and a meandering conductive heater. An average thickness and surface roughness of $0.99~\mu \text{m}$ and $0.23~\mu \text{m}$ , respectively, was registered for the printed MWCNTs sensing layer. The capability of the printed sensor, with heater, was investigated by subjecting it to relative humidity (RH) ranging from 10% to 90%. The response demonstrated an overall resistance change of 55% when the sensor was subjected to 90% RH, when compared to 10% RH. A maximum hysteresis of 5.1%, at 70% RH, was calculated for the resistive response of the sensor. The printed sensors can be bend with radius of curvature of 1.5 inch with literally no effect.

71 citations

Journal ArticleDOI
TL;DR: In this article, a micro-structured polydimethylsiloxane (PDMS) dielectric layer was developed for wearable E-skin and touch sensing applications, which was fabricated on a flexible polyethylene terephthalate (PET) substrate.
Abstract: A novel capacitive pressure sensor based on micro-structured polydimethylsiloxane (PDMS) dielectric layer was developed for wearable E-skin and touch sensing applications. The pressure sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate, using PDMS and silver (Ag) as the dielectric and electrode layers, respectively. A set of PDMS films with pyramid shaped micro-structures were fabricated using a laser engraved acrylic mold. The electrodes (top and bottom) were fabricated by depositing Ag on PET films using additive screen-printing process. The pressure sensor was assembled by attaching the top and bottom Ag electrodes to the smooth side of pyramid shaped micro-structured PDMS (PM-PDMS) films. The top PM-PDMS was then placed on the bottom PM-PDMS. The capability of the fabricated pressure sensor was investigated by subjecting the sensor to pressures ranging from 0 to 10 kPa. A sensitivity of 0.221% Pa $^{\mathbf {-1}}$ , 0.033% Pa $^{\mathbf {-1}}$ and 0.011% Pa $^{\mathbf {-1}}$ along with a correlation coefficient of 0.9536, 0.9586 and 0.9826 was obtained for the pressure sensor in the pressure range of 0 Pa to 100 Pa, 100 Pa to 1000 Pa, and 1 kPa to 10 kPa, respectively. The pressure sensor also possesses a fast response time of 50 ms, low hysteresis of 0.7%, recovery time of 150 ms and excellent cycling stability over 1000 cycles. The results demonstrated the efficient detection of pressure generated from various activities such as hand gesture and carotid pulse measurement. The PM-PDMS based pressure sensor offers a simple and cost-effective approach to monitor pressure in E-skin applications.

61 citations