1,721,104 research outputs found
Data supporting the article "Battery-Free Wireless Light-Sensing Tag based on a Long-Range Dual-Port Dual-Polarized RFID Platform"
No full textData supporting the article "Battery-Free Wireless Light-Sensing Tag based on a
Long-Range Dual-Port Dual-Polarized RFID Platform" by Wagih, Mahmoud, Alex S. Weddell, and Steve Beeby (2022) in Sensors 22, no. 13: 4782. https://doi.org/10.3390/s22134782.
The dataset reports experimental data including:
Gain - Simulated antenna gain values
MIMORFID_<...> - Measured antenan input impedance in different operation conditions, labelled in the file name.
RadPatterns - Comparison of the simulated and measured RFID radiation patterns
This project was funded by EPSRC Wearable and Autonomous Computing for Future Smart Cities - Platform Grant, EP/P010164/1
and by "Radio Frequency-Enabled Multi-Source Energy Harvesting in Inaccessible Environments", ICRF2122-5-104.
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On the Moisture-Resilience of On-Body Surface Wave Single Wire Transmission Lines (SWTLs)
No full textRadio Frequency (RF) surface wave transmission lines support low-loss on-body propagation, and have recently attracted significant interest for wearables. In this work, the effect of fabric moisture absoption on a surface-wave textile Single Wire Transmission Line (SWTL) is analyzed in the Ultra High-Frequency (UHF) spectrum from 0.5 to 4 GHz. It is shown that moisture can increase the losses (in dB) by four-fold. The42 cm SWTL maintains an insertion loss around 15 dB up to at 2.4 GHz, when the substrate is covered fully in water. The measured response is compared to a printed textile micro strip line; the surface-wave SWTL exhibits a more linear response to the moisture content indicating its suitability for RF moisture sensing applications
Phase-accurate analytical transmission line model and for a 1--50 GHz millimeter-wave textile-based wearable Goubau Single Wire Transmission Line (SWTL)
No full textGoubau-Sommerfeld Single Wire Transmission Lines (SWTLs) are a feasible approach for low-loss high-speed transmission. However, the long length of an SWTL makes full-wave electromagnetic simulations too computationally intensive. In this paper, a transmission line model is proposed for a state-of-the-art textile-based wearable broadband millimeter-wave SWTL, which represents the first broadband closed-form analytical model for a wearable surface wave transmission line. The inductance and capacitance are calculated per unit length using closed-form formulas and used to construct a simple SWTL equivalent circuit based on the lossy transmission line model. The analytically calculated phase exhibits under 7% error compared to vector network analyzer (VNA) measurements from 2 to 50 GHz. The VNA measurements are then used to fit the loss terms in the model leading to a good agreement between calculations, full-wave simulations, and experiments. It is anticipated that the developed model and low-cost mmWave SWTL will empower future integration of low-loss SWTLs in different applications without the need for complex numerical simulations
Battery-free wireless node powered using high-efficiency harvesting of 900 MHz GFSK- modulated packets with a compact rectenna
No full textRadio Frequency (RF) Simultaneous Wireless Information and Power Transfer (SWIPT) has attracted significant interest with a range of SWIPT-specific rectenna implementations. However, the impact of modulated waveforms on a capacitor charging time remains unknown, and a system powered off packets us yet to be demonstrated. This paper presents an RF-powered sub-1 GHz sensor node through modulated packages with a sub-0 dBm sensitivity without any DC-DC power management circuitry. Using Gaussian Frequency Shift Keying (GFSK) modulated signals from a commercial IoT transceiver, the RF-DC power conversion efficiency (PCE) is investigated for both a resistive and capacitive load. It is shown that GFSK modulation with varying data rates has minimal influence on the PCE. A miniaturized rectenna is demonstrated charging a supercapacitor powering a sub-1 GHz sensor node for over 32 s, charged using 40 GFSK packets transmitted in 62 s, at 1.6 m from a 4 W circularly-polarized source at 900 MHz. The demonstrated rectenna exhibits over an order of magnitude improvement in the sensitivity over previous works harvesting modulated packets
Broadband low-loss on-body UHF to millimeter-wave surface wave links using flexible textile single wire transmission lines
Full text linkOn-body transmission represents a challenge due to human body shadowing. This paper proposes a Sommerfeld-Goubau single-wire transmission line (SWTL) implemented using electronic textiles for low-loss on-body links up to millimeter-wave frequencies, overcoming the spherical spreading loss and on-body absorption. The SWTL is fabricated using a conductive thread suitable for embroidery on textiles. A compact tapered launcher is implemented on a flexible polyimide substrate to excite the surface mode along the SWTL. In space, a 3 m-long line maintains a forward transmission over -10 dB between 1 and 3 GHz. The SWTL link is characterized for different body parts showing under 20 dB insertion loss with a 1 cm air gap. Across the torso, a forward transmission over -20 dB is maintained from 0.5 to 2.5 GHz, which represents at least 20 dB improvement over two antennas, of larger dimensions, over-the-air. Directly on-skin, the SWTL can be used around 1 GHz with an S21 over -25 dB, over 50 dB improvement over two on-skin antennas. At 50 GHz, the shielded SWTL exhibits an ultra-low on-body attenuation around 0.11 dB/mm, a four-fold improvement over a microstrip line on the same substrate. It is concluded that SWTLs can enable ultra high-speed future body area networks
Direct-write dispenser printing for rapid antenna prototyping on thin flexible substrates
No full textRapid prototyping of antennas is crucial to validation of simulation models when designing conformal antennas on unusual substrates such as polymers and textiles. This paper presents direct-write dispenser printing, using a commercial Printed Circuit Board (PCB) printer, as a simple mean of prototyping planar antennas on ultra-thin (25 \mu m) flexible Polyimide substrates. Two Coplanar Waveguide (CPW) monopole antennas have been designed for the 2.4 GHz band and fabricated using dispenser printing and standard photolithography. The impedance bandwidth and gain of both antennas has been compared and the printed prototype was found to match the performance of the etched antenna within a 2.6% and 2.3% margin respectively, as well as matching the full-wave 3D simulation of the connectorized antennas. Based on the measured performance of the printed antenna, the potential of utilising commercial dispenser printers to prototype and manufacture low-volume antennas for low-cost unobtrusive Internet of Things applications is demonstrated.</p
An investigation of meshed printed monopoles for optically-transparent antennas
No full textMeshed antennas have recently attracted interest for applications where optical-transparency is required [1]. For additively manufactured antennas, the conductive ink used and subsequently the cost of the antenna can be significantly reduced by meshing the antenna’s conductors and ground plane [2]. Despite their wide presence in microstrip patch antennas [3] and more recently for complex-impedance dipoles [2], wide-band coplanar waveguide (CPW) antennas have not been explored with meshed radiators or ground planes. In this paper, a 2.4 GHz monopole is designed and characterized numerically and experimentally for various mesh fill-factors, showing over 2.3 dBi measured gain for up to 93% theoretical transparency
Comments on “A Passive and Wireless SensorBased on RFID Antenna for Detecting Mechanical Deformation”
No full textHe et al. proposed a mechanical deformation sensor based on a microstrip patch antenna matched to a radiofrequency identification (RFID) integrated circuit (IC). In Fig. 6in [1], a near-field coupled RFID system was shown, whereas the developed system operated in the far-field region. This comment presents a more representative figure explaining the operation principle of UHF RFID system, supplementing the information in [1
Towards improved IoT LoRa-WAN connectivity using broadband omnidirectional antennas
No full textDespite the growing volume of Long Range (LoRa) wide area networks (WAN) devices, there is limited research on the antenna's influence on a node's connectivity. In this paper, the channel gain of an 868 MHz LoRa-Wan node in an urban environment is used to evaluate the performance of different antennas, as well as evaluate motion, elevation, and shadowing effects on the nodes connectivity. A dual-transmitter node with two tightly-coupled antennas is utilized to characterize the channel gain between the antenna-under-test, and multiple indoor and outdoor gateways over 1 km away, through the relative signal strength (RSS). It is demonstrated that using a broadband UWB-inspired monopole implemented on an inexpensive cardboard substrate, the channel gain can be improved over commercially available whip antennas
Complex-impedance dipole antennas as RFID-enabled ice monitors
No full textRFID tags can operate in a wide variety of environments enabling battery-free pervasive sensing. In this paper, time-varying impedance measurements are presented to evaluate the sensitivity of inductive-matched dipole antennas as ice thawing monitors. Relative Signal Strength (RSS) measurements of an encapsulated RFID tags based on a commercial IC are presented showing that the tags can be read for up to 45 minutes inside 9~mm-thick thawing ice. Furthermore, the relationship between the ice thickness and the RSS of the ice-loaded RFID tags. The experimental results show that inductive-fed dipole antennas are highly suited for RFID-based monitoring of ice formation and thawing for smart city and remote sensing applications
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