Pub Date : 2022-03-22DOI: 10.3389/felec.2022.813535
Arunprabaharan Subramanian, Mona Azimi, Cheng Yee Leong, S. Lee, C. Santato, F. Cicoira
Titanium dioxide (TiO2) is an abundant metal oxide, widely used in food industry, cosmetics, medicine, water treatment and electronic devices. TiO2 is of interest for next-generation indium-free thin-film transistors and ion-gated transistors due to its tunable optoelectronic properties, ambient stability, and solution processability. In this work, we fabricated TiO2 films using a wet chemical approach and demonstrated their transistor behavior with room temperature ionic liquids and aqueous electrolytes. In addition, we demonstrated the pH sensing behavior of the TiO2 IGTs with a sensitivity of ∼48 mV/pH. Furthermore, we demonstrated a low temperature (120°C), solution processed TiO2-based IGTs on flexible polyethylene terephthalate (PET) substrates, which were stable under moderate tensile bending.
{"title":"Solution-Processed Titanium Dioxide Ion-Gated Transistors and Their Application for pH Sensing","authors":"Arunprabaharan Subramanian, Mona Azimi, Cheng Yee Leong, S. Lee, C. Santato, F. Cicoira","doi":"10.3389/felec.2022.813535","DOIUrl":"https://doi.org/10.3389/felec.2022.813535","url":null,"abstract":"Titanium dioxide (TiO2) is an abundant metal oxide, widely used in food industry, cosmetics, medicine, water treatment and electronic devices. TiO2 is of interest for next-generation indium-free thin-film transistors and ion-gated transistors due to its tunable optoelectronic properties, ambient stability, and solution processability. In this work, we fabricated TiO2 films using a wet chemical approach and demonstrated their transistor behavior with room temperature ionic liquids and aqueous electrolytes. In addition, we demonstrated the pH sensing behavior of the TiO2 IGTs with a sensitivity of ∼48 mV/pH. Furthermore, we demonstrated a low temperature (120°C), solution processed TiO2-based IGTs on flexible polyethylene terephthalate (PET) substrates, which were stable under moderate tensile bending.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43182388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The switching patterns and gate resistor of the Si/SiC hybrid switch are the key to realizing its own highly efficient and reliable operation. However, as an important performance indicator, the common mode (CM) electromagnetic interference (EMI) noise caused by the Si/SiC hybrid switch lacks comprehensive research, which means that it is not clear how the switching patterns and gate resistor affect CM EMI. In this paper, the Si/SiC hybrid switch-based boost converter is established at first. Then, by analyzing the spectral characteristics of the CM voltage of the Si/SiC hybrid switch, the CM EMI generation characteristics of the Si/SiC hybrid switch at different switching patterns and gate resistors are revealed. Furthermore, the analysis and experimental results can be used to comprehensively guide the design of the gate drive pattern, gate resistor, and EMI suppression strategy.
{"title":"Study on the CM EMI Generation Characteristics of the Si/SiC Hybrid Switch at Different Switching Patterns and Gate Resistors","authors":"Yong Zhu, Zishun Peng, Yuxing Dai, Zhenxing Zhao, Zeng Liu, Zijie Zheng","doi":"10.3389/felec.2021.789902","DOIUrl":"https://doi.org/10.3389/felec.2021.789902","url":null,"abstract":"The switching patterns and gate resistor of the Si/SiC hybrid switch are the key to realizing its own highly efficient and reliable operation. However, as an important performance indicator, the common mode (CM) electromagnetic interference (EMI) noise caused by the Si/SiC hybrid switch lacks comprehensive research, which means that it is not clear how the switching patterns and gate resistor affect CM EMI. In this paper, the Si/SiC hybrid switch-based boost converter is established at first. Then, by analyzing the spectral characteristics of the CM voltage of the Si/SiC hybrid switch, the CM EMI generation characteristics of the Si/SiC hybrid switch at different switching patterns and gate resistors are revealed. Furthermore, the analysis and experimental results can be used to comprehensively guide the design of the gate drive pattern, gate resistor, and EMI suppression strategy.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41870135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-09DOI: 10.3389/felec.2022.838472
A. Falco, Antonio Marín-Sánchez, F. Loghin, Encarnación Castillo, A. Salinas-Castillo, J. F. Salmerón, A. Rivadeneyra
Flexible and thin-film humidity sensors are currently attracting the attention of the scientific community due to their portability and reduced size, which are highly useful traits for use in the Internet o Things (IoT) industry. Furthermore, in order to perform efficient and profitable mass production, it is necessary to develop a cost-effective and reproducible fabrication process and materials. Green fabrication methods and biodegradable materials would also minimize the environmental impact and create a sustainable IoT development. In this paper, flexible humidity sensors based on a common salt (NaCl) sensing layer are reported. Our sensors and the fabrication techniques employed, such as dip and spray coating, provide a biodegradable, low cost, and highly reproducible device. One of the sensors reported presents a typical resistive behaviour from 40% RH up to 85% RH with a sensitivity of −0.21 (Z/%RH). The performance of the sensors obtained with several fabrication techniques is studied and reported at multiple frequencies from 100 Hz to 10 MHz, showcasing its versatility and robustness.
{"title":"Paper and Salt: Biodegradable NaCl-Based Humidity Sensors for Sustainable Electronics","authors":"A. Falco, Antonio Marín-Sánchez, F. Loghin, Encarnación Castillo, A. Salinas-Castillo, J. F. Salmerón, A. Rivadeneyra","doi":"10.3389/felec.2022.838472","DOIUrl":"https://doi.org/10.3389/felec.2022.838472","url":null,"abstract":"Flexible and thin-film humidity sensors are currently attracting the attention of the scientific community due to their portability and reduced size, which are highly useful traits for use in the Internet o Things (IoT) industry. Furthermore, in order to perform efficient and profitable mass production, it is necessary to develop a cost-effective and reproducible fabrication process and materials. Green fabrication methods and biodegradable materials would also minimize the environmental impact and create a sustainable IoT development. In this paper, flexible humidity sensors based on a common salt (NaCl) sensing layer are reported. Our sensors and the fabrication techniques employed, such as dip and spray coating, provide a biodegradable, low cost, and highly reproducible device. One of the sensors reported presents a typical resistive behaviour from 40% RH up to 85% RH with a sensitivity of −0.21 (Z/%RH). The performance of the sensors obtained with several fabrication techniques is studied and reported at multiple frequencies from 100 Hz to 10 MHz, showcasing its versatility and robustness.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48741437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-03DOI: 10.3389/felec.2021.790081
H. Son, James D. Weiland
Independent travelling is a significant challenge for visually impaired people in urban settings. Traditional and widely used aids such as guide dogs and long canes provide basic guidance and obstacle avoidance but are not sufficient for complex situations such as street crossing. We propose a new wearable system that can safely guide a user with visual impairment at a signalized crosswalk. Safe street crossing is an important element of fully independent travelling for people who are blind or visually impaired (BVI), but street crossing is challenging for BVI because it involves several steps reliant on vision, including scene understanding, localization, object detection, path planning, and path following. Street crossing also requires timely completion. Prior solutions for guiding BVI in crosswalks have focused on either detection of crosswalks or classifying crosswalks signs. In this paper, we demonstrate a system that performs all the functions necessary to safely guide BVI at a signalized crosswalk. Our system utilizes prior maps, similar to how autonomous vehicles are guided. The hardware components are lightweight such that they can be wearable and mobile, and all are commercially available. The system operates in real-time. Computer vision algorithms (Orbslam2) localize the user in the map and orient them to the crosswalk. The state of the crosswalk signal (don’t walk or walk) is detected (using a convolutional neural network), the user is notified (via verbal instructions) when it is safe to cross, and the user is guided (via verbal instructions) along a path towards a destination on the prior map. The system continually updates user position relative to the path and corrects the user’s trajectory with simple verbal commands. We demonstrate the system functionality in three BVI participants. With brief training, all three were able to use the system to successfully navigate a crosswalk in a safe manner.
{"title":"Wearable System to Guide Crosswalk Navigation for People With Visual Impairment","authors":"H. Son, James D. Weiland","doi":"10.3389/felec.2021.790081","DOIUrl":"https://doi.org/10.3389/felec.2021.790081","url":null,"abstract":"Independent travelling is a significant challenge for visually impaired people in urban settings. Traditional and widely used aids such as guide dogs and long canes provide basic guidance and obstacle avoidance but are not sufficient for complex situations such as street crossing. We propose a new wearable system that can safely guide a user with visual impairment at a signalized crosswalk. Safe street crossing is an important element of fully independent travelling for people who are blind or visually impaired (BVI), but street crossing is challenging for BVI because it involves several steps reliant on vision, including scene understanding, localization, object detection, path planning, and path following. Street crossing also requires timely completion. Prior solutions for guiding BVI in crosswalks have focused on either detection of crosswalks or classifying crosswalks signs. In this paper, we demonstrate a system that performs all the functions necessary to safely guide BVI at a signalized crosswalk. Our system utilizes prior maps, similar to how autonomous vehicles are guided. The hardware components are lightweight such that they can be wearable and mobile, and all are commercially available. The system operates in real-time. Computer vision algorithms (Orbslam2) localize the user in the map and orient them to the crosswalk. The state of the crosswalk signal (don’t walk or walk) is detected (using a convolutional neural network), the user is notified (via verbal instructions) when it is safe to cross, and the user is guided (via verbal instructions) along a path towards a destination on the prior map. The system continually updates user position relative to the path and corrects the user’s trajectory with simple verbal commands. We demonstrate the system functionality in three BVI participants. With brief training, all three were able to use the system to successfully navigate a crosswalk in a safe manner.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46268130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-18DOI: 10.3389/felec.2022.834146
G. Singh, Ankit Wagle, S. Khatri, S. Vrudhula
This paper presents a DRAM-based processing-in-memory (PIM) architecture, called CIDAN-XE. It contains a novel computing unit called the neuron processing element (NPE). Each NPE can perform a variety of operations that include logical, arithmetic, relational, and predicate operations on multi-bit operands. Furthermore, they can be reconfigured to switch operations during run-time without increasing the overall latency or power of the operation. Since NPEs consume a small area and can operate at very high frequencies, they can be integrated inside the DRAM without disrupting its organization or timing constraints. Simulation results on a set of operations such as AND, OR, XOR, addition, multiplication, etc., show that CIDAN-XE achieves an average throughput improvement of 72X/5.4X and energy efficiency improvement of 244X/29X over CPU/GPU. To further demonstrate the benefits of using CIDAN-XE, we implement several convolutional neural networks and show that CIDAN-XE can improve upon the throughput and energy efficiency over the latest PIM architectures.
{"title":"CIDAN-XE: Computing in DRAM with Artificial Neurons","authors":"G. Singh, Ankit Wagle, S. Khatri, S. Vrudhula","doi":"10.3389/felec.2022.834146","DOIUrl":"https://doi.org/10.3389/felec.2022.834146","url":null,"abstract":"This paper presents a DRAM-based processing-in-memory (PIM) architecture, called CIDAN-XE. It contains a novel computing unit called the neuron processing element (NPE). Each NPE can perform a variety of operations that include logical, arithmetic, relational, and predicate operations on multi-bit operands. Furthermore, they can be reconfigured to switch operations during run-time without increasing the overall latency or power of the operation. Since NPEs consume a small area and can operate at very high frequencies, they can be integrated inside the DRAM without disrupting its organization or timing constraints. Simulation results on a set of operations such as AND, OR, XOR, addition, multiplication, etc., show that CIDAN-XE achieves an average throughput improvement of 72X/5.4X and energy efficiency improvement of 244X/29X over CPU/GPU. To further demonstrate the benefits of using CIDAN-XE, we implement several convolutional neural networks and show that CIDAN-XE can improve upon the throughput and energy efficiency over the latest PIM architectures.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46074815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-18DOI: 10.3389/felec.2022.833260
Simon Thomann, Hong L. G. Nguyen, P. Genssler, H. Amrouch
The separation of computing units and memory in the computer architecture mandates energy-intensive data transfers creating the von Neumann bottleneck. This bottleneck is exposed at the application level by the steady growth of IoT and data-centric deep learning algorithms demanding extraordinary throughput. On the hardware level, analog Processing-in-Memory (PiM) schemes are used to build platforms that eliminate the compute-memory gap to overcome the von Neumann bottleneck. PiM can be efficiently implemented with ferroelectric transistors (FeFET), an emerging non-volatile memory technology. However, PiM and FeFET are heavily impacted by process variation, especially in sub 14 nm technology nodes, reducing the reliability and thus inducing errors. Brain-inspired Hyperdimensional Computing (HDC) is robust against such errors. Further, it is able to learn from very little data cutting energy-intensive transfers. Hence, HDC, in combination with PiM, tackles the von Neumann bottleneck at both levels. Nevertheless, the analog nature of PiM schemes necessitates the conversion of results to digital, which is often not considered. Yet, the conversion introduces large overheads and diminishes the PiM efficiency. In this paper, we propose an all-in-memory scheme performing computation and conversion at once, utilizing programmable FeFET synapses to build the comparator used for the conversion. Our experimental setup is first calibrated against Intel 14 nm FinFET technology for both transistor electrical characteristics and variability. Then, a physics-based model of ferroelectric is included to realize the Fe-FinFETs. Using this setup, we analyze the circuit’s susceptibility to process variation, derive a comprehensive error probability model, and inject it into the inference algorithm of HDC. The robustness of HDC against noise and errors is able to withstand the high error probabilities with a loss of merely 0.3% inference accuracy.
{"title":"All-in-Memory Brain-Inspired Computing Using FeFET Synapses","authors":"Simon Thomann, Hong L. G. Nguyen, P. Genssler, H. Amrouch","doi":"10.3389/felec.2022.833260","DOIUrl":"https://doi.org/10.3389/felec.2022.833260","url":null,"abstract":"The separation of computing units and memory in the computer architecture mandates energy-intensive data transfers creating the von Neumann bottleneck. This bottleneck is exposed at the application level by the steady growth of IoT and data-centric deep learning algorithms demanding extraordinary throughput. On the hardware level, analog Processing-in-Memory (PiM) schemes are used to build platforms that eliminate the compute-memory gap to overcome the von Neumann bottleneck. PiM can be efficiently implemented with ferroelectric transistors (FeFET), an emerging non-volatile memory technology. However, PiM and FeFET are heavily impacted by process variation, especially in sub 14 nm technology nodes, reducing the reliability and thus inducing errors. Brain-inspired Hyperdimensional Computing (HDC) is robust against such errors. Further, it is able to learn from very little data cutting energy-intensive transfers. Hence, HDC, in combination with PiM, tackles the von Neumann bottleneck at both levels. Nevertheless, the analog nature of PiM schemes necessitates the conversion of results to digital, which is often not considered. Yet, the conversion introduces large overheads and diminishes the PiM efficiency. In this paper, we propose an all-in-memory scheme performing computation and conversion at once, utilizing programmable FeFET synapses to build the comparator used for the conversion. Our experimental setup is first calibrated against Intel 14 nm FinFET technology for both transistor electrical characteristics and variability. Then, a physics-based model of ferroelectric is included to realize the Fe-FinFETs. Using this setup, we analyze the circuit’s susceptibility to process variation, derive a comprehensive error probability model, and inject it into the inference algorithm of HDC. The robustness of HDC against noise and errors is able to withstand the high error probabilities with a loss of merely 0.3% inference accuracy.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41639772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-07DOI: 10.3389/felec.2022.837260
R. Mastria, V. Pecunia, A. Rizzo
Over the last couple of decades, the development of innovative hybrid materials, spanning from colloidal nanocrystals to hybrid halide perovskites, has offered novel and unpredictable functionalities. This fact has stimulated the development of optoelectronic devices with the potential of overcoming technological and cost constraints of current inorganic counterparts. In this research topic, we have collected a selection of both original research and review articles covering different hybrid material synthesis and device application aspects. These articles also demonstrate the increasing interest in the development of emerging innovative hybrid materials for next-generation optoelectronic devices. Thanks to their outstanding photophysical prerogatives, metal halide perovskites are among the most appealing materials for innovative optoelectronic device applications. Nonetheless, the development of lead-free perovskites is a highly desirable prospect in view of a truly industrial deployment. In this frame, Veronese et al. report the development of a series of lead-free perovskite colloidal nanocrystals compositions Cs2SnX6 (X = Br, I) with different shapes. Tin-halide perovskitebased nanocrystals were selected as a valid alternative to lead. Since Sn (II) tends to easily oxidize into Sn (IV), tin-based perovskites suffer in general from a severe chemical instability that deteriorates their photophysical and optoelectronic properties. To overcome the oxidation issue of tin, the authors propose a modified hot-injection procedure in which Sn (II) can be replaced with Sn (IV). Varying the metal oxidation number results in the formation of a new crystal structure: the so-called vacancy-ordered double perovskite. They screen the effect of various surface ligands, finding that long-chain oleic acid ligands induce the formation of 3D colloidal nanocrystals, whereas shorter chain amines favour the growth of 2D nanoplatelets. A complete picture of the correlation between crystalline structure and optical properties of the as developed lead-free nanocrystal with the ligand molecule length and the nanocrystal shape is offered. Another burgeoning family of materials that have captured considerable interest for optoelectronic applications involves quasi-zero-dimensional halide perovskite derivatives. Given the diversity of their embodiments, properties, and applications, the review article by Trifiletti et al. on the topic constitutes a particularly valuable contribution as it provides a comprehensive, crosssectional picture of the status of this area. A great deal of different materials is discussed, including lead-based compounds as well as lead-free ones—e.g., based on tin, bismuth, and antimony—while highlighting the salient similarities and differences between hybrid and fully inorganic embodiments. A particular merit of this review lies in the discussion of the materials and their properties through a uniquely comprehensive treatment of the corresponding p
{"title":"Editorial: Next Generation Optoelectronics With Emerging Hybrid Materials","authors":"R. Mastria, V. Pecunia, A. Rizzo","doi":"10.3389/felec.2022.837260","DOIUrl":"https://doi.org/10.3389/felec.2022.837260","url":null,"abstract":"Over the last couple of decades, the development of innovative hybrid materials, spanning from colloidal nanocrystals to hybrid halide perovskites, has offered novel and unpredictable functionalities. This fact has stimulated the development of optoelectronic devices with the potential of overcoming technological and cost constraints of current inorganic counterparts. In this research topic, we have collected a selection of both original research and review articles covering different hybrid material synthesis and device application aspects. These articles also demonstrate the increasing interest in the development of emerging innovative hybrid materials for next-generation optoelectronic devices. Thanks to their outstanding photophysical prerogatives, metal halide perovskites are among the most appealing materials for innovative optoelectronic device applications. Nonetheless, the development of lead-free perovskites is a highly desirable prospect in view of a truly industrial deployment. In this frame, Veronese et al. report the development of a series of lead-free perovskite colloidal nanocrystals compositions Cs2SnX6 (X = Br, I) with different shapes. Tin-halide perovskitebased nanocrystals were selected as a valid alternative to lead. Since Sn (II) tends to easily oxidize into Sn (IV), tin-based perovskites suffer in general from a severe chemical instability that deteriorates their photophysical and optoelectronic properties. To overcome the oxidation issue of tin, the authors propose a modified hot-injection procedure in which Sn (II) can be replaced with Sn (IV). Varying the metal oxidation number results in the formation of a new crystal structure: the so-called vacancy-ordered double perovskite. They screen the effect of various surface ligands, finding that long-chain oleic acid ligands induce the formation of 3D colloidal nanocrystals, whereas shorter chain amines favour the growth of 2D nanoplatelets. A complete picture of the correlation between crystalline structure and optical properties of the as developed lead-free nanocrystal with the ligand molecule length and the nanocrystal shape is offered. Another burgeoning family of materials that have captured considerable interest for optoelectronic applications involves quasi-zero-dimensional halide perovskite derivatives. Given the diversity of their embodiments, properties, and applications, the review article by Trifiletti et al. on the topic constitutes a particularly valuable contribution as it provides a comprehensive, crosssectional picture of the status of this area. A great deal of different materials is discussed, including lead-based compounds as well as lead-free ones—e.g., based on tin, bismuth, and antimony—while highlighting the salient similarities and differences between hybrid and fully inorganic embodiments. A particular merit of this review lies in the discussion of the materials and their properties through a uniquely comprehensive treatment of the corresponding p","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46839931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-03DOI: 10.3389/felec.2021.807051
David Yang, Shovan Maity, Shreyas Sen
Human body communication (HBC) has recently emerged as an alternative method to connect devices on and around the human body utilizing the electrical conductivity properties of the human body. HBC can be utilized to enable new interaction modalities between computing devices by enhancing the natural interaction of touch. It also provides the inherent benefit of security and energy-efficiency compared to a traditional wireless communication, such as Bluetooth, making it an attractive alternative. However, most state-of-the-art HBC demonstrations show communication between a wearable and an Earth ground–connected device, and there have been very few implementations of HBC systems demonstrating communication between two wearable devices. Also, most of the HBC implementations suffer from the problem of signal leakage out of the body which enables communication even without direct contact with the body. In this article, we present BodyWire which uses an electro-quasistatic HBC (EQS-HBC) technique to enable communication between two wearable devices and also confine the signal to a very close proximity to the body. We characterize the human body channel loss under different environment (office desk, laboratory, and outdoors), posture, and body location conditions to ascertain the effect of each of these on the overall channel loss. The measurement results show that the channel loss varies within a range of 15dB across all different posture, environmental conditions, and body location variation, illustrating the dynamic range of the signal available at the input of any receiver. Leakage measurements are also carried out from the devices to show the distance over which the signal is available away from the body to illustrate the security aspect of HBC and show its effect on the channel loss measurements. For the first time, a through-body interhuman channel loss characterization is presented. Finally, a demonstration of secure interhuman information exchange between two battery-operated wearable devices is shown through the BodyWire prototype, which shows the smallest form factor HBC demonstration according to the authors’ best knowledge.
{"title":"Physically Secure Wearable–Wearable Through-Body Interhuman Body Communication","authors":"David Yang, Shovan Maity, Shreyas Sen","doi":"10.3389/felec.2021.807051","DOIUrl":"https://doi.org/10.3389/felec.2021.807051","url":null,"abstract":"Human body communication (HBC) has recently emerged as an alternative method to connect devices on and around the human body utilizing the electrical conductivity properties of the human body. HBC can be utilized to enable new interaction modalities between computing devices by enhancing the natural interaction of touch. It also provides the inherent benefit of security and energy-efficiency compared to a traditional wireless communication, such as Bluetooth, making it an attractive alternative. However, most state-of-the-art HBC demonstrations show communication between a wearable and an Earth ground–connected device, and there have been very few implementations of HBC systems demonstrating communication between two wearable devices. Also, most of the HBC implementations suffer from the problem of signal leakage out of the body which enables communication even without direct contact with the body. In this article, we present BodyWire which uses an electro-quasistatic HBC (EQS-HBC) technique to enable communication between two wearable devices and also confine the signal to a very close proximity to the body. We characterize the human body channel loss under different environment (office desk, laboratory, and outdoors), posture, and body location conditions to ascertain the effect of each of these on the overall channel loss. The measurement results show that the channel loss varies within a range of 15dB across all different posture, environmental conditions, and body location variation, illustrating the dynamic range of the signal available at the input of any receiver. Leakage measurements are also carried out from the devices to show the distance over which the signal is available away from the body to illustrate the security aspect of HBC and show its effect on the channel loss measurements. For the first time, a through-body interhuman channel loss characterization is presented. Finally, a demonstration of secure interhuman information exchange between two battery-operated wearable devices is shown through the BodyWire prototype, which shows the smallest form factor HBC demonstration according to the authors’ best knowledge.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47530997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-21DOI: 10.3389/felec.2021.762442
Maggie K. Delano, V. Ganapati, Rezhwan Kamal, Bryan D. Le, Jackie Le, Rey Mendoza
Fluid overload is a chronic medical condition that affects over six million Americans with conditions such as congestive heart failure, end-stage renal disease, and lymphedema. Remote management of fluid overload continues to be a leading clinical challenge. Bioimpedance is one technique that can be used to estimate the hydration of tissue and track it over time. However, commercially available bioimpedance measurement systems are bulky, expensive, and rely on Ag/AgCl electrodes that dry out and can irritate the skin. The use of bioimpedance today is therefore limited to clinical and research settings, with measurements performed at daily intervals or over short periods of time rather than continuously and long-term. This paper proposes using wearable calf bioimpedance measurements integrated into a compression sock for long-term fluid overload management. A PCB was developed using standard measurement techniques that measures the calf bioimpedance using a custom analog front-end built around an AD8302 gain-phase detection chip. Data is transmitted wirelessly via Bluetooth Low Energy to an iOS device using a custom iOS app. Bioimpedance data were collected both from the wearable system and a commercial measurement system (ImpediMed SFB7) using RRC networks, Ag/AgCl electrodes, and the textile compression sock. Bioimpedance data collected from the wearable system showed close agreement with data from the SFB7 when using RRC networks and in five healthy human subjects with Ag/AgCl electrodes. However, when using the textile compression sock the wearable system had worse precision than the SFB7 (4% run to run compared to < 1 % run to run) and there were larger differences between the two systems than when using the RRC networks and the Ag/AgCl electrodes. Wearable system precision and agreement with the SFB7 was improved by pressure or light wetting of the current electrodes on the sock. Future research should focus on reliable elimination of low-frequency artifacts in research grade hardware to enable long-term calf bioimpedance measurements for fluid overload management.
{"title":"Evaluating Research Grade Bioimpedance Hardware Using Textile Electrodes for Long-Term Fluid Status Monitoring","authors":"Maggie K. Delano, V. Ganapati, Rezhwan Kamal, Bryan D. Le, Jackie Le, Rey Mendoza","doi":"10.3389/felec.2021.762442","DOIUrl":"https://doi.org/10.3389/felec.2021.762442","url":null,"abstract":"Fluid overload is a chronic medical condition that affects over six million Americans with conditions such as congestive heart failure, end-stage renal disease, and lymphedema. Remote management of fluid overload continues to be a leading clinical challenge. Bioimpedance is one technique that can be used to estimate the hydration of tissue and track it over time. However, commercially available bioimpedance measurement systems are bulky, expensive, and rely on Ag/AgCl electrodes that dry out and can irritate the skin. The use of bioimpedance today is therefore limited to clinical and research settings, with measurements performed at daily intervals or over short periods of time rather than continuously and long-term. This paper proposes using wearable calf bioimpedance measurements integrated into a compression sock for long-term fluid overload management. A PCB was developed using standard measurement techniques that measures the calf bioimpedance using a custom analog front-end built around an AD8302 gain-phase detection chip. Data is transmitted wirelessly via Bluetooth Low Energy to an iOS device using a custom iOS app. Bioimpedance data were collected both from the wearable system and a commercial measurement system (ImpediMed SFB7) using RRC networks, Ag/AgCl electrodes, and the textile compression sock. Bioimpedance data collected from the wearable system showed close agreement with data from the SFB7 when using RRC networks and in five healthy human subjects with Ag/AgCl electrodes. However, when using the textile compression sock the wearable system had worse precision than the SFB7 (4% run to run compared to < 1 % run to run) and there were larger differences between the two systems than when using the RRC networks and the Ag/AgCl electrodes. Wearable system precision and agreement with the SFB7 was improved by pressure or light wetting of the current electrodes on the sock. Future research should focus on reliable elimination of low-frequency artifacts in research grade hardware to enable long-term calf bioimpedance measurements for fluid overload management.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43778120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-07DOI: 10.3389/felec.2021.804474
Sami Bolat, Evangelos Agiannis, Shih‐Chi Yang, Moritz H. Futscher, Abdesselam Aribia, I. Shorubalko, Y. Romanyuk
Solution processing and low-temperature annealing (T < 300°C) of the precursor compounds promise low-cost manufacturing for future applications of flexible oxide electronics. However, thermal budget reduction comes at the expense of increased charge trapping residuals in the dielectric layers, which result in hysteretic switching of transistors. This work reports on a novel bilayer dielectric scheme combining aluminum oxide (AlOx) as a positive charge trapping insulator and yttrium aluminum oxide (YAlOx) as a negative charge trapping dielectric to obtain hysteresis free switching in the solution-processed metal-oxide thin-film transistors. Devices were processed at a thermal budget of 250°C, without an encapsulation layer. The presence of H+ and OH− in the AlOx were found responsible for the hysteresis in the switching, which was suppressed successfully with the thickness optimization of the YAlOx in the dielectric stack. Fabricated devices yield ON/OFF ratios of 106, sub-pA level gate leakage currents, a subthreshold swing of 150 mV/decade, and field-effect mobility of 1.5 cm2/V-sec.
{"title":"Engineering Bilayer AlOx /YAlOx Dielectric Stacks for Hysteresis-Free Switching in Solution-Processed Metal-Oxide Thin-Film Transistors","authors":"Sami Bolat, Evangelos Agiannis, Shih‐Chi Yang, Moritz H. Futscher, Abdesselam Aribia, I. Shorubalko, Y. Romanyuk","doi":"10.3389/felec.2021.804474","DOIUrl":"https://doi.org/10.3389/felec.2021.804474","url":null,"abstract":"Solution processing and low-temperature annealing (T < 300°C) of the precursor compounds promise low-cost manufacturing for future applications of flexible oxide electronics. However, thermal budget reduction comes at the expense of increased charge trapping residuals in the dielectric layers, which result in hysteretic switching of transistors. This work reports on a novel bilayer dielectric scheme combining aluminum oxide (AlOx) as a positive charge trapping insulator and yttrium aluminum oxide (YAlOx) as a negative charge trapping dielectric to obtain hysteresis free switching in the solution-processed metal-oxide thin-film transistors. Devices were processed at a thermal budget of 250°C, without an encapsulation layer. The presence of H+ and OH− in the AlOx were found responsible for the hysteresis in the switching, which was suppressed successfully with the thickness optimization of the YAlOx in the dielectric stack. Fabricated devices yield ON/OFF ratios of 106, sub-pA level gate leakage currents, a subthreshold swing of 150 mV/decade, and field-effect mobility of 1.5 cm2/V-sec.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42323618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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