1,721,050 research outputs found
Design, prototyping, and characterization of laser-induced graphene antennas on flexible substrates: consolidating current knowledge
No full textLaser-induced graphene (LIG) is a widespread technology for the manufacturing of low-cost and eco-friendly sensors that can be also exploited for the fabrication of conductorless antennas and RF devices for the personal and industrial Internet of Things (IoT). In this case, additional issues must be accounted for, such as the much larger lasing area, the moderate conductivity of LIG, and the durability versus environmental and mechanical conditions in real applications, but also new opportunities to provide antennas with nonconventional features. This article provides a unitary representation of the state-of-the-art knowledge for the modeling, design, fabrication, and testing of LIG-based antennas at some frequencies of IoT systems. The reader will find information about the selection of materials, how to configure the laser parameters to minimize the sheet resistance, and how to account for the moderate conductivity in numerical solvers. The upper bound performances are identified and related to the optimal antenna size. As IoT devices include sensors, the integration with the antenna can benefit from nonuniform lasing to dump unwanted RF currents on the sensor while preserving the communication capability. Finally, the immunity of LIG antennas to external stimuli is reviewed to quantify the expected degradation of performance. This tutorial hence provides a multidisciplinary background to activate a new research line, as well as to conduct experiments with the new concept of antennas engraved on substrates
Ultra Low Power Wireless Epidermal Sensor for Battery-less pH monitoring in the sub-6 GHz 5G band
No full textRFID epidermal electronics recently gave us the possibility to connect our body to the external world and gather information about our health and state directly from the skin. To increase the acceptance of the monitoring platforms and overcome the limitations of current technology, i.e. the need of a dedicated reader and a limited bandwidth, new architectures of battery-less backscattering-based communications have been considered. Among them, 5G appears particularly promising thanks to the large bandwidth, the interoperability among devices and the pervasive coverage. In this perspective, this paper proposes the first epidermal chemical sensor for the sampling of the human sweat and the monitoring of the pH. The device communicates with the external reader through a frequency modulation of the backscattered wave, whose parameters depend on the measured analyte. Early simulations and tests corroborate the feasibility of the approach
Full-LIG Wireless Batteryless Sensor for the Detection of Amines
No full textFood waste management at the global level requires new technologies for an item-level monitoring of the volatile molecules emitted by food inside the package. The use of conventional chemical sensors requiring complex electronics is prevented at the large scale by not affordable costs. A possible solution can come from the Laser-Induced Graphene (LIG) technology that permits to impress a complex circuit onto a polymeric substrate by means of laser engraving. We here propose the first zero-power wireless sensors on polyimide for amine detection, useful for hazard evaluation in case of consumption, where both the interdigitated sensor and the communication antenna are entirely made by LIG with non-uniform lasing parameters. The device is flexible, is capable of detecting less than 15% concentration of triethylamine and is readable up to 1.5m by resorting to the backscattering modulation framework of Radiofrequency Identification in the UHF band
Wireless Bilateral Breath Monitoring System Using Temperature-Based Wearable Technology in Motion
No full textRFID Technology for Food Industry 4.0: a review of solutions and applications
No full textThe emerging fourth industrial revolution is revolutionizing the food industry, which has historically been plagued by food waste and contamination. Several internet-of-things (IoT) technologies have been proposed for optimizing processes and reducing costs while improving health conditions and safety in food consumption. Among them, radiofrequency identification (RFID) has been considered from the beginning a key instrument, especially in food logistics and management. Many contributions and case studies from academia and industry demonstrated the strategic role and the impact on existing and future paradigms of food. The literature analysis in the present work suggests a growing interest in RFID to implement optimization procedures for food management and control. This review describes RFID employment in three pillars of the Fourth Generation of the Food Industry (FI4.0): Logistics, Sensing, and Green RFID. The logistics one comprises the most mature applications for RFID, such as cold-chain monitoring or product tracking. Food sensing, instead, is currently the most attractive research area for both industry and academia, so researchers are focusing their attention on detecting physical and chemical parameters through direct and indirect sensing approaches. Furthermore, the ever-increasing amount of electronic waste motivated the research community to provide sustainable tags to establish Green RFID devices. According to this literature review, RFID can foster the fourth industrial revolution in food, especially considering the emerging synergy with artificial intelligence and biodegradable/resorbable materials
Upper Bound Performances of Laser-Induced Graphene Dipoles in the UHF Band
No full textLaser ablation can easily create graphene traces through the photothermal conversion of polymeric films. The so-obtained graphene, known as Laser-Induced Graphene (LIG), is eco-friendly, biocompatible and easy to produce, making it a promising option for creating flexible and conformable electronics for environmentally friendly and cost-effective communication over short to medium distances.Since LIG conductivity is significantly lower than that of standard conductors, the radiation efficiency of a LIG-antenna does not increase in a straightforward manner as expected for lossy materials. Hence, in this paper, we numerically and experimentally varied the length of a dipole antenna to identify the ideal size to achieve maximum radiation efficiency.The results showed that the lasing parameters that affect the properties of LIG only have an impact on the maximum radiation efficiency, and partly on the antenna size. Additionally, even with the most conductive LIG and optimal size, the radiation efficiency was still only 2 dB lower than that of copper
Experimental characterization of Laser Induced Graphene (LIG) antennas for S-band wearable applications in 5G
No full textWidespreading 5G communication in the Internet of Things demands for eco-friendly antennas to avoid e-waste. Graphene is one of the most innovative materials with low environmental impact. To overcome its manufacturing complexity, laser scribing techniques have been recently developed. By means of a high power CO2 laser, polymers such as Polyimide are converted into a porous form of Graphene (LIG). In this paper, LIG is experimentally characterized in DC under different environmental conditions. Then its radiative performances are investigated by comparing them with the same copper-based antenna for S-band wearable communications. Experimentation revealed that the LIG antenna is practically insensitive to even variable environmental conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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