1,720,993 research outputs found
Capacitively-coupled UHF antennas for wireless temperature monitoring of bearings in electric vehicles
No full textThis work introduces a capacitively-coupled telemetry system operating in the UHF band (868-960 MHz). It is based on two concentric C-shaped dipoles positioned at a millimeter distance. Numerical simulations have been employed to optimize the angular dimensions of the antennas, and the resulting arrangement ensures a stable link for any mutual orientation. Preliminary experiments conducted with a mock-up have demonstrated that sensing and communication through backscattering modulation can be achieved with only 400 μW of power
RFID interface for compact pliable EMG wireless epidermal sensor
No full textThe growth of epidermal electronics requires
low-cost, compact, wireless and low-power consumer
technologies. Commercially available electromyographic
(EMG) sensors do not fully meet these requirements.
Radiofrequency Identification (RFID) is a low-cost wireless
communication technology that helps in reducing sensor size
and power requests. This work proposes the design of a 3cm x
3cm RFID antenna surrounding an ad hoc EMG sensor
circuitry and supporting the mid-range data communication
between 40cm – 1m. The resulting RFID-EMG sensor is a
compact, pliable and conformable device, suitable for sport,
wellness, healthcare and medical applications
Near-field circular array for the transcutaneous telemetry of UHF RFID-based implantable medical devices
No full textWireless communication with Implantable Medical Devices (IMDs) based on Radiofrequency Identification in the UHF band suffers from the constraints on the maximum power absorbed by the body tissues. Accordingly, an interrogating antenna placed onto the skin is capable to monitor only a limited region just below its footprint. In some applications like the hand prosthesis controlled by Electromyographic signals emitted by muscle contractions, multiple IMDs have to be used to increase the degrees of freedom in driving the actuators. An array of interrogators, working in the near-field can mitigate this bottleneck by greatly extend the read region inside the body. Sequentially- and simultaneously-fed arrays by a same reader are here investigated to optimize the multi-sensor backscattering modulated links. The conditions (feeding scheme and alignment) to guarantee a robust interrogation of a relevant number of implanted sensors with no battery onboard are identified also accounting for the safety constraints related to the SAR. Numerical simulations and experimentation with a cylindrical phantom resembling human limbs, hosting reference antennas, demonstrate that the simultaneous feed permits to interact with eight IMDs by using nearly all the available power from typical readers (30 dBm, 22 dBm as a minimum) without exceeding the SAR limit with a power margin (w.r.t. sensor-oriented ICs with −10 dBm power sensitivity) of more than 5 dB for any angular alignment between the array and the sensors
A Fully Integrated On-Skin RFID EMG Sensor
No full textWe designed, fabricated, and tested a UHF RFID-based wireless system for electromyographic sensing, differently from the usual RFID employment on TAGs. The design leads to a fully integrated system, not electromagnetically interfering with the analogic part of the board, thus preserving the very low signal coming from the electromyographic activity of the muscles. Whilst wireless transmission usually represents the greater power contribution, our solution has the advantage of a compact design to easily implement data transfer passive communication, without onboard energy consumption. We optimized the analog output of the EMG sensor to properly interface the input of the analog to digital converter that is embedded in the RFID chip. A test exploiting three hand gestures confirmed the expected results, and the collected and transmitted EMG signal is compliant with the same signal sampled with an oscilloscope, thus promoting further advancements to reduce the overall system dimensions and the analog power requirements
Performance evaluations of UHF-RFID flexible antennas fully-integrated with epidermal sensor board
No full textBio-integrated wireless systems require to integrate electronic modules for bio-signal processing within a stretchable and soft skin-like device. The size and complexity of the PCB hosting circuitry cannot be separated from the design of the antenna used for the communication. Challenges arise when high frequencies are involved so that human body losses will deteriorate the radiation gain. This paper describes the design of a UHF-RFID epidermal antenna integrated with different types of EMG-sensor board arrangements in comparison with a benchmark configuration. The purpose is to evaluate the effect of the PCB metallization and identify the optimal antenna size. An overall 40 × 40 mm2 device footprint is found to minimize the disturbing effects of the sensor circuit on the antenna performance and a read range up to 150 cm can be achieved
Experimental assessment of wireless monitoring of axilla temperature by means of epidermal battery-less RFID sensors
No full textApparati storico artistici e miglioramento sismico nel restauro post-sisma. Nuovo approccio metodologico,
No full text“The restoration of historical, artistic and decorative features and the seismic improvement of the structures are interventions that interact between themselves...” [1] and the project of the interventions must be integrated and cannot be seen separately. For the restoration of historical artistic heritage, the MIBAC guidelines provide for the Artistic Limit State that needs to be deepened taking into account the strong connection with the structure. Seismic safety is a consequence of these aspects and the analysis of seismic risk should include a critical reading of all the vulnerability indicators of the structure and of the artistic assets connected to it. The authors developed a methodological approach experimented in the restoration and seismic improvement of some historical buildings located in L'Aquila and damaged by the earthquake of 2009, including the Church of “Santa Maria della Misericordia” (AQ), where compatible interventions with the preexistence were identified. At the same time, these interventions can guarantee the preservation of the historical building and the safety of all its components. This contribution therefore intends to illustrate the methodology developed, then verified in the aforementioned case study
A General-Purpose Small RFID Epidermal Datalogger for Continuous Human Skin Monitoring in Mobility
No full textSkin sensors based on Radiofrequency Identification enable non-invasive monitoring of human physiologic parameters. To speed up the experimentations of new sensing modalities and their possible applications, a general purpose on-skin oriented board is here described. A 3 cm by 3 cm flexible Kapton layer hosts a miniaturized open-loop antenna tunable in the worldwide UHF RFID band (860-960)MHz, a microchip with internal ADC and pads for interconnecting external sensors and a battery for data-logging mode. The epidermal board can be integrated into plasters and is suitable to measure both skin and external parameters. When working in Battery Assisted Passive mode it can be read up to 1.5 m and hence the wearer can automatically upload the stored data in mobility on crossing a gate. The device is preliminarily experimented in the measurement of the temperature of the skin and of the moisture on clothes
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