526 research outputs found
Dataset supporting the publication: Towards the Optimal Antenna-Based Wireless Sensing Strategy: An Ice Sensing Case Study
No full textData supporting the article by M. Wagih and J. Shi, "Toward the Optimal Antenna-Based Wireless Sensing Strategy: An Ice Sensing Case Study," in IEEE Open Journal of Antennas and Propagation, vol. 3, pp. 687-699, 2022, doi: 10.1109/OJAP.2022.3182770.
This dataset contains:
Raw data that explores angular radiation patterns, simulated gain changes vs. humidity (substrate E_r) and <...>sparameters.csv as well as measured time-varying s-parameters of the antenna-based sensing system in different measurement setups.
The data contains excel files:
-Antenna_Gain_simulations.csv
-Dipole Antenna Freezing TimeVariation.csv
-Humidity_sensitivity.csv
-Loop Antenna Freezing TimeVariations.csv
-Loop antenna in tube freezing.csv
-Loop antenna simulated patterns.csv
-Thickness calculations.csv
</span
Dataset for Flexible 2.4 GHz Node for Body Area Networks with a Compact High-Gain Planar Antenna
No full textDataset for the Paper titled "Flexible 2.4 GHz Node for Body Area Networks with a Compact High-Gain Planar Antenna", in the IEEE Antennas and Wireless Propagation Letters.
Also related to: Wagih, M., Wei, Y., Yong, S., & Beeby, S. (2018). Connecting and powering flexible IoT, an insole case study. Poster session presented at Arm Research Summit 2018, Cambridge, United Kingdom.</span
Towards Solution-Processed RF Rectennas: Experimental Characterization and Non-Linear Modelling based on ZnO Nanogap Diodes
No full textThe growing demands of the IoT market call for novel ultra-low-cost RF semiconductor devices. Using GHz-frequency Schottky diodes fabricated on a wafer-scale, low-cost natively flexible rectennas and RF energy harvesters can be realized. This paper will present, for the first time, the non-linear model followed by antenna-circuit co-design for solution-processed Zinc-Oxide (ZnO) Schottky diodes. The diode's equiv-alent circuit model is extracted and compared to experimental on-wafer characterization showing very good agreement up to 40 GHz. Using a complex-impedance source emulating a printable rectenna, the designed voltage doubler rectifier shows a power conversion efficiency up to 70% in the UHF RFID band (0.915 GHz). The optimum source and load impedance parameters for a single-series and voltage-doubler rectifier are finally presented, showing that ZnO nano-gap diodes can be adopted in future rectenna designs
Correction: Todorov et al. Electromagnetic Sensing Techniques for Monitoring Atopic Dermatitis—Current Practices and Possible Advancements: A Review. Sensors 2023, 23, 3935
No full text**Mahmoud Wagih** was not included as an author in the original publication [...
Wireless ice detection and monitoring using flexible UHF RFID tags
No full textOwing to its low relative permittivity, very fewmicrowave sensors have been developed for monitoring icedeposition. This paper presents the first use of UHF RFIDtags for wireless RF ice sensing applications. Despite its lowpermittivity, the existence of ice as a superstrate on a planarultra-thin dipole antenna can lower the resonance frequency ofthe antenna significantly. The RFID tags, having a measuredunloaded range of 9.4 m, were evaluated for remotely detectingthe formation of ice in various scenarios up to 10 m from thereader, as well as monitoring the ice thawing, based on theRelative Signal Strength (RSS) in a phase-free approach. In mostRSS-based sensing approaches, the tag’s read-range is reducedas the RSS decreases in response to the stimulant. However, theproposed sensing mechanism does not reduce the tag’s range;the ice superstrate improves the impedance matching of the tagsand increases their radar cross section (RCS), resulting in a10 m loaded read-range with over 12 dB ice-sensitivity, in anechoic multi-path environment. The proposed sensing mechanismachieves an accuracy of 86% for tags positioned between 0.5 and10.5 m with various obstructions. When subjected to line-of-sightmetallic obstruction, the sensor still maintains 80% accuracy. Thelong range and high sensitivity of the proposed sensing mechanicsshow that UHF RFID is a promising method for detecting theformation of ice in future smart cities
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
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
No full textOn-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
Thin flexible RF energy harvesting rectenna surface with a large effective aperture for sub µW/cm2 powering of wireless sensor nodes
No full textThe dc power collected by radio frequency energy harvesting (RFEH) absorbing surfaces is limited by their physical aperture. Here, a compact, conformable, and ultrathin sub-1 GHz large-area RFEH surface is proposed based on electrically small ( ka=0.58 ) “wire-type” rectenna elements, with an effective area exceeding its physical aperture size. Using optimized large-signal complex source tuning, the rectifiers achieve up to 36% measured power conversion efficiency (PCE) at 20 dBm. The proposed 15 cm-diameter six-element array generates a 27.5 μ W at 1 V output from a 0.17 μ W/cm 2 incident power density across a 40 k Ω load. Owing to its series connection, the voltage output is boosted, and the load resistance dependence is suppressed enabling over 60% of the maximum RF-to-dc PCE to be preserved for loads between 7 and 100 k Ω , with an area-normalized figure-of-merit nearly 100% higher than previous arrays. The proposed array is integrated with a commercial DC-DC converter and demonstrated powering a Bluetooth low energy (BLE) wireless sensor node (WSN) from an unprecedented incident power density of 0.25 μ W/cm 2 . A practical demonstration using a commercial 3 W, 915 MHz Powercast source is presented, showing an 11 m operation range with a 1 V output and illustrating the impact of polarization mismatch on the proposed array
Characterizing and modelling non-linear Rectifiers for RF energy harvesting
No full textRadio Frequency Energy Harvesting and power transfer, using rectifying antennas, are increasingly seen as an enabling technology of power-autonomous devices. The non-linearity of the rectification element, the diode, adds challenges when experimentally characterizing and comparing the performance of different rectifiers, requiring complex measurement techniques to characterize a diode experimentally, and adds to the challenges of designing a matching network. This paper presents a method for characterizing the power conversion of a mismatched rectifier using a single-port vector network analyzer, omitting the need for impedance tuners and accurately reflecting the non-linearity of the diode. The proposed approach minimizes uncertainty sources in the test setup and shows close agreement with optimized harmonic balance simulation. Finally, harmonic balance simulation is utilized to compare the source and load impedance of the two most common rectifier topologies, a single series and a voltage doubler, acting as a guide for matching network and antenna design
- …
