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1
Abdulhussein, Nabil, und Abdulkareem Abdullah. „Design of a Wide Dual-Band Coplanar Probe Feed Antenna for WLANs Applications“. 3D SCEEER Conference sceeer, Nr. 3d (01.07.2020): 13–16. http://dx.doi.org/10.37917/ijeee.sceeer.3rd.2.
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This paper presents a new design to obtain wide dual-band operation from a coplanar probe feed antenna loaded with two shorted walls. The lower band of proposed antenna has a 10 dB bandwidth of 611 MHz (24.18%) around the center frequency 2527MHz, and the upper band has a bandwidth of 1255 MHz (27.88%) around the center frequency 4501MHz. The obtained bandwidths cover WLANs operations on all bands. The bandwidth of the first operating frequency covers ISM band (2400-2483.5) MHz, which is required by IEEE 802.11b, g and Bluetooth standards, and the bandwidth of the second operating frequency covers U-NII1 (5150-5350) MHz band, which is required by IEEE 802.11a and HiperLAN2 standards, and also covers U-NII2 (5470-5725) MHz and U-NII3/ISM (5725-5825) MHz bands, which are required by IEEE 802.11a standard. A three dimensional finite-difference time-domain (3-D FDTD) method is employed to analyze the proposed structure and find its performance. The simulated results are compared with the experimental results.
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Wu, Chih-Kuang, Tsung-Fu Chien, Chin-Lung Yang und Ching-Hsing Luo. „Design of Novel S-Shaped Quad-Band Antenna for MedRadio/WMTS/ISM Implantable Biotelemetry Applications“. International Journal of Antennas and Propagation 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/564092.
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A novel S-shaped quad-band planar inverted-F antenna (PIFA) is proposed for implantable biotelemetry in the Medical Device Radiocommunications Service (MedRadio) band (401–406 MHz), Wireless Medical Telemetry Service (WMTS) band (1427–1432 MHz), and industrial, scientific, and medical (ISM) bands (433-434 MHz and 2.4–2.4835 GHz). The proposed antenna reveals compact dimension of 254 mm3(10×10×2.45 mm3) and is composed of three substrates and a superstrate, which are constructed from an S-shaped radiator (layer 1) and two twin radiators of spiral structures (layer 2 and layer 3). The optimal antenna characteristics were measured in the ground pork skin, and the measured bandwidths are 150 MHz for the MedRadio and ISM bands (433 MHz), 52 MHz for the WMTS band, and 102 MHz for the ISM band (2.4 GHz), respectively. The characteristics of proposed antenna are enough to support the applications of implantable body area networks (BAN) for biotelemetry and can completely cover main available frequency bands of BAN for biotelemetry below 3 GHz.
3
Singla, Geetanjali, Rajesh Khanna und Davinder Parkash. „CPW fed rectangular rings-based patch antenna with DGS for WLAN/UNII applications“. International Journal of Microwave and Wireless Technologies 11, Nr. 5-6 (21.02.2019): 523–31. http://dx.doi.org/10.1017/s1759078719000023.
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AbstractThe spectral congestion in existing Industrial, Scientific, and Medical (ISM) Wireless Local Area Network (WLAN) bands has led to the emergence of new ISM bands (Unlicensed National Information Infrastructure (UNII)) from 5.150 to 5.710 GHz. In this paper, a simple uniplanar, high gain, microstrip antenna is designed, fabricated, and tested for existing WLAN and new UNII standards. The proposed antenna provides dualband operation by joining two rectangular rings and cutting Defected Ground Structure in the Coplanar Wave Guide (CPW) feed. The experimental and simulation results show good return loss characteristics and stable radiation pattern over the desired frequency bands ranging from 2.20 to 2.65 GHz (WLAN band) at a lower frequency and from 5.0 to 5.45 GHz (UNII-1/UNII-2 bands). The measured peak gains are 5.5 and 4.9 dBi at 2.45 GHz (WLAN band) and 5.15 GHz (UNII band), respectively.
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Zahraoui, I., A. Errkik, M. C. Abounaima, A. Tajmouati, L. E. Abdellaoui und M. Latrach. „A New Planar Multiband Antenna for GPS, ISM and WiMAX Applications“. International Journal of Electrical and Computer Engineering (IJECE) 7, Nr. 4 (01.08.2017): 2018. http://dx.doi.org/10.11591/ijece.v7i4.pp2018-2026.
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In this paper a design of a new antenna with modified ground plane is validated for multiband applications. The proposed modified ground structure is incorporated with a patch antenna to boost the performance. The antenna’s entire area is 59.5x47mm<sup>2</sup> and is printed on an FR-4 substrate and fed by a 50 Ohm microstrip line. This structure is validated in the GPS (1.56-1.58 GHz) band at 1.57 GHz, in the ISM (2.43-2.49 GHz) band at 2.45GHz and in the WiMAX (3.50-3.56 GHz) band at 3.53 GHz. These three frequency bands have good matching input impedance for, S11≤-10 dB. The antenna presents a good performance in terms of radiation pattern, and it is designed, optimized, and miniaturized by using CST-MW whose results are compared with other solvers HFSS and ADS. The results obtained by the use of the three EM solvers are in good agreement. After realization, we have tested and validated this antenna. The measurement results of the antenna present a good agreement with the numerical results.
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Mansour, Mohamed M., Shota Torigoe, Shuya Yamamoto und Haruichi Kanaya. „Compact and Simple High-Efficient Dual-Band RF-DC Rectifier for Wireless Electromagnetic Energy Harvesting“. Electronics 10, Nr. 15 (23.07.2021): 1764. http://dx.doi.org/10.3390/electronics10151764.
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(1) Background: This work presents a high-efficiency, high sensitivity, compact rectifier based on a dual-band impedance matching network that employs a simple and straightforward T-matching circuit, for sub-1 GHz license-free applications. The development of a low-cost RF energy harvester dedicated to the ISM bands is introduced. The proposed rectifier design is optimized to operate at the sub-GHz frequency bands (0.9 to 2.4 GHz), specifically those at the ISM 900 and 2400 MHz. The motivation for this band is due to the low attenuation, well-known fundamental electromagnetic theories and background, and several wireless communications are emitting at those bands, such as RFID (2). Methods: The rectifier design is based on a simple, balanced single-series diode connected with a T-matching circuit. The dual-band performance is achieved by deploying reactive elements in each branch. The full mathematical analysis and simulation results are discussed in the manuscript. (3) Results: The rectifier can achieve a 80 MHz bandwidth around 920 MHz frequency and 200 MHz around the higher band 2.4 GHz. The resultant conversion efficiency level is maintained above 45% at both bands with a peak efficiency reaches up to 70% at the higher band. The optimum terminal load attached to the circuit at which the peak efficiency is achieved, is given as 4.7 kΩ. (4) Conclusion: Due to the compactness and small footprint, simple design, and simple integration with microwave circuits, the proposed rectifier architecture might find several potential applications in wireless RF energy harvesting.
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Jain, Chahat, und Saroop Singh. „Feed Point Optimization of Koch–Minkowski Hybrid Boundary antenna for ISM Band“. Wireless Personal Communications 108, Nr. 4 (09.05.2019): 2403–14. http://dx.doi.org/10.1007/s11277-019-06528-2.
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Al-Obaidi, Mohammed K., Ezri Mohd, Noorsaliza Abdullah, Samsul Haimi Dahlan und Jawad Ali. „Design and implementation of microstrip rotman lens for ISM band applications“. Bulletin of Electrical Engineering and Informatics 8, Nr. 1 (01.03.2019): 90–98. http://dx.doi.org/10.11591/eei.v8i1.1392.
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This work presents the design and implementation of Rotman lens as a beam steering device for Industrial, Scientific, and Medical (ISM) applications. 2.45 GHz is considered as a center frequency design with (2-6) GHz frequency bandwidth. The beam steering is examined to cover ±21o scan angle with maximum main lobe magnitude 10.1 dBi, rectangular patch antennas are used as radiation elements to beam the output far field. The work is extended to compare between the tapered line which is used for matching between 50-Ω ports and lens cavity. CST microwave simulation studio results show that the rectangular taper line can yield 2 dB return loss less than linear taper line with a little bit shifting in responses for same input and load impedance.
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Madhav, Boddapati T. P., Shaik Rajiya, Badugu P. Nadh und Munuswami S. Kumar. „Frequency reconfigurable monopole antenna with DGS for ISM band applications“. Journal of Electrical Engineering 69, Nr. 4 (01.08.2018): 293–99. http://dx.doi.org/10.2478/jee-2018-0041.
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Abstract In this article a compact frequency reconfigurable antenna is presented for wireless communication applications of industrial, scientific and medical band (ISM). The proposed antenna model is designed with the dimensions of 58mm×48 mm on FR4 epoxy of dielectric constant 4.4 with the thickness of 0.8 mm. The proposed antenna consists of defected T-shape ground plane, which acts as a reflector. In the design of frequency reconfigurable antenna, BAR 64-02V PIN diodes are used as switching elements and antenna is fed by microstrip transmission line. The proposed antenna can switch at different frequencies (2.5 GHz, 2.3 GHz and 2.2 GHz) depending on the biasing voltage applied to the PIN diodes. The current antenna showing VSWR < 2 in the operating band and providing peak realized gain of 3.2 dBi. A good matching obtained between expected and the measured results.
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Gupta, Monish, Vikas Mittal, Jyoti Saxena und Sushma Gupta. „Miniaturized Microstrip Patch Antenna Array for ISM Band Using Complementary Split Ring Resonator“. Wireless Personal Communications 109, Nr. 4 (22.08.2019): 2251–62. http://dx.doi.org/10.1007/s11277-019-06679-2.
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Khan, Faisal A., Chris Rizos und Andrew G. Dempster. „Locata Performance Evaluation in the Presence of Wide- and Narrow-Band Interference“. Journal of Navigation 63, Nr. 3 (28.05.2010): 527–43. http://dx.doi.org/10.1017/s037346331000007x.
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Classically difficult positioning environments often call for augmentation technology to assist the GPS, or more generally the Global Navigation Satellite System (GNSS) technology. The “Locata” ground-based ranging technology offers augmentation, and even replacement, to GPS in such environments. However, like any other system relying on wireless technology, a Locata positioning network also faces issues in the presence of RF interference (RFI). This problem is magnified due to the fact that Locata operates in the licence-free 2·4 GHz Industrial, Scientific and Medical (ISM) band. The licence-free nature of this band attracts a much larger number of devices using a wider range of signal types than for licensed bands, resulting in elevation of the noise floor. Also, harmonics from out-of-band signals can act as potential interferers. WiFi devices operating in this band have been identified as the most likely potential interferer, due partially to their use of the whole ISM band, but also because Locata applications often also may use a wireless network. This paper evaluates the performance of Locata in the presence of both narrow- and wide-band interfering signals. Effects of received interference on both raw measurements and final solutions are reported and analysed. Test results show that Locata performance degrades in the presence of received interference. It is also identified that high levels of received interference can affect Locata carriers even if the interference is not in co-frequency situation with the affected carrier. Finally, Locata characteristics have been identified which can be exploited to mitigate RFI issues.
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Kishore, M. Purna, B. T. P. Madhav und S. S. Mohan Reddy. „Metamaterial Inspired Gain Enhanced Elliptical Curved CPW fed Multiband Antenna for Medical and Wireless Communication Applications“. Biomedical and Pharmacology Journal 12, Nr. 2 (25.06.2019): 729–37. http://dx.doi.org/10.13005/bpj/1695.
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This article presents a novel elliptical curved coplanar waveguide fed antenna with defected ground. Electromagnetic coupling between splitring resonator (SRR) on other side to the substrate to CPW feeding line on the top side resulting the frequency notches in the wideband. The SRR shaped etched portion in the ground plane not only miniaturizing the antenna, but also providing good bandwidth in the operating bands. Antenna providing multiband characteristics for PCS, Bluetooth, LTE, ISM (Medical Application Band) and Wi-Fi communication (2-3.6 GHz), WLAN IEEE 802.11a/h/j/n (4.5-5.825 GHz), satellite system X-band downlink (7.5-9 GHz) and satellite communication applications at (12-16 GHz) & (17.5-18.5 GHz) respectively. This antenna offering quad band notching with penta band operation from 2-20 GHz. The size of the antenna is 40X44X1.6 mm with peak gain value of 7.18 dB with average efficiency parameter more than 68%. The manufactured antenna prototype is tested for validation and the obtained measurement matching with respect to the optimized simulation result.
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Hao, Hong Gang, Wen Shuai Hu, Hai Yan Tian und Yi Ren. „A Dual-Band LTCC Antenna with Cross Circuitous Structure“. Advanced Materials Research 601 (Dezember 2012): 163–67. http://dx.doi.org/10.4028/www.scientific.net/amr.601.163.
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A compact dual-band antenna for ISM (2.45GHz) or WiMAX (3.15GHz) applications by low-temperature co-fired ceramic (LTCC) technology is presented in this paper. The proposed antenna is composed of multi-layer structures to reduce the sizes effectively. The simulated results show that the dimensions of the antenna are 11×4.2×1.2mm3, with the 2:1 VSWR impedance bandwidth definition, the lower and upper band have the bandwidth of 80 and 90 MHz. The novel antenna has realized miniaturization and omni-directional radiation patterns across the whole operating frequency band.
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Bondonneau, Louis, Jean-Mathias Grießmeier, Gilles Theureau und Maciej Serylak. „Low frequency pulsar observations with the international LOFAR station FR606“. Proceedings of the International Astronomical Union 13, S337 (September 2017): 313–14. http://dx.doi.org/10.1017/s1743921317009656.
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AbstractThe pulsar’s signal passes through the interstellar medium (ISM) which leads to both chromatic dispersive delays and multipath pulse broadening. These effects have a strong frequency dependence (f−2 and f−4 respectively). Pulse profiles of pulsars are also frequency-dependent leading to some degeneracy with the ISM imprint. Furthermore, many pulsars show a turnover of their spectrum around ~100 MHz. For all these reasons, the frequency band below 100 MHz contains a lot of information about both the pulsar emission and the ISM. Our study is based on a LOw Frequency ARray (LOFAR) monitoring campaign using the international station FR606. Firstly, we demonstrate the importance of a monitoring campaign. Secondly, we calculate median spectra and locate the turnover frequency for 3 pulsars (B0809+74, B1133+16, B1508+55).
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Kaka, Ademola O., Mehmet Toycan und Stuart D. Walker. „Miniaturized stacked implant antenna design at ISM band with biocompatible characteristics“. COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, Nr. 4 (06.07.2015): 1270–85. http://dx.doi.org/10.1108/compel-02-2015-0032.
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Purpose – A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiator-based patch antenna is proposed and characterized for medical implant applications at the Industrial, Scientific and Medical band (2.4-2.48 GHz). Antenna parameters are optimised to achieve miniaturized, biocompatible and stable transmission characteristics. The paper aims to discuss these issues. Design/methodology/approach – Human tissue effects on the antenna electrical characteristics were simulated with a three-layer (skin, fat and muscle) human tissue model with the dimensions of 180×70×60 mm3 (width×height×thickness mm3). Different stacked substrates are utilized for the satisfactory characteristics. Two identical radiating patches are printed on Roger 3,010 (ε r=10.2) and Alumina (ε r=9.4) substrate materials, respectively. In addition, various superstrate materials are considered and simulated to prevent short circuit the antenna while having a direct contact with the metallization, and achieve biocompatibility. Finally, superstrate material of Zirconia (ε r=29) is used to achieve biocompatibility and long-life. A finite element method is used to simulate the proposed hybrid model with commercially available Ansoft HFSS software. Findings – The antenna is miniaturized, having dimensions of 10×8.4×2 mm3 (width×height×thickness mm3). The resonance frequency of the antenna is 2.4 GHz with a bandwidth of 100 MHz at return loss (S11) of better than −10 dB characteristics. Overall, the proposed antenna have 50 Ω impedance matching, −21 dB far field antenna gain, single-plane omni-directional radiation pattern properties and incident power of 5.3 mW to adhere Specific Absorption Rate regulation limit. Originality/value – Vertically stacked three layer hybrid design have miniaturized characteristics, wide bandwidth, biocompatible, and stable characteristics in three layer human tissue model make this antenna suitable for implant biomedical monitor systems. The advanced simulation analysis of the proposed design constitutes the main contribution of the paper.
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Januszkiewicz, Łukasz, Paolo Di Barba, Łukasz Jopek und Sławomir Hausman. „Many-Objective Automated Optimization of a Four-Band Antenna for Multiband Wireless Sensor Networks“. Sensors 18, Nr. 10 (02.10.2018): 3309. http://dx.doi.org/10.3390/s18103309.
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This paper describes a new design and an optimization framework for a four-band antenna to be used in wireless sensor networks. The antenna is designed to operate effectively in two open frequency bands (ISM—Industrial, Scientific, Medical), 2.4 GHz and 5.8 GHz, as well as in two bands allocated for the fifth-generation (5G) cellular networks, 0.7 GHz and 3.5 GHz. Our initial design was developed using the trial and error approach, modifying a circular disc monopole antenna widely used in ultra wideband (UWB) systems. This initial design covered the three upper bands, but impedance matching within the 700 MHz band was unsatisfactory. The antenna performance was then improved significantly using an optimization algorithm that applies a bi-objective fully-Paretian approach to its nine-parameter geometry. The optimization criteria were impedance matching and radiation efficiency. The final design exhibits good impedance matching in all four desired bands with the Voltage Standing Wave Ratio (VSWR) value below 2 and radiation efficiency of 88%. The simulated antenna performance was verified experimentally.
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Alshamaileh, K. A., M. J. Almalkawi und V. K. Devabhaktuni. „Dual Band-Notched Microstrip-Fed Vivaldi Antenna Utilizing Compact EBG Structures“. International Journal of Antennas and Propagation 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/439832.
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We propose an ultra-wideband (UWB) antipodal Vivaldi antenna (AVA) with high-Qstopband characteristics based on compact electromagnetic bandgap (EBG) structures. First, an AVA is designed and optimized to operate over an UWB spectrum. Then, two pairs of EBG cells are introduced along the antenna feed line to suppress the frequency components at 3.6–3.9 and 5.6–5.8 GHz (i.e., WiMAX and ISM bands, resp.). Simulated and measured results show a voltage standing wave ratio (VSWR) below 2 for the entire 3.1–10.6 GHz band with high attenuation at the two selected subbands. This simple yet effective approach eliminates the need to deform the antenna radiators with slots/parasitic elements or comprise multilayer substrates. Furthermore, the flexibility it offers in terms of controlling both the number and locations of the band-reject frequencies is advantageous for antennas with nonuniform flares as in the AVA.
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Islam, Md Shazzadul, Muhammad I. Ibrahimy, S. M. A. Motakabber, A. K. M. Zakir Hossain und S. M. Kayser Azam. „Microstrip patch antenna with defected ground structure for biomedical application“. Bulletin of Electrical Engineering and Informatics 8, Nr. 2 (01.06.2019): 586–95. http://dx.doi.org/10.11591/eei.v8i2.1495.
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Proper narrowband antenna design for wearable devices in the biomedical application is a significant field of research interest. In this work, defected ground structure-based microstrip patch antenna has been proposed that can work for narrowband applications. The proposed antenna works exactly for a single channel of ISM band. The resonant frequency of the antenna is 2.45 GHz with a return loss of around -30 dB. The -10dB impedance bandwidth of the antenna is 20 MHz (2.442-2.462 GHz), which is the bandwidth of channel 9 in ISM band. The antenna has achieved a high gain of 7.04 dBi with an increase of 17.63% antenna efficiency in terms of realized gain by using defected ground structure. Three linear vector arrays of arrangement 1 2, 1 4 and 1 8 have been designed to validate the proposed antenna performances as an array. The proposed antenna is light weighted, low cost, easy to fabricate and with better performances that makes it suitable for biomedical WLAN applications.
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Skemer, Andrew J., Laird M. Close, Philip M. Hinz, William F. Hoffmann, Thomas P. Greene, Jared R. Males und Tracy L. Beck. „ISM DUST GRAINS ANDN-BAND SPECTRAL VARIABILITY IN THE SPATIALLY RESOLVED SUBARCSECOND BINARY UY Aur,“,. Astrophysical Journal 711, Nr. 2 (23.02.2010): 1280–90. http://dx.doi.org/10.1088/0004-637x/711/2/1280.
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Popovic, Zoya. „Wireless powering for low-power distributed sensors“. Serbian Journal of Electrical Engineering 3, Nr. 2 (2006): 149–62. http://dx.doi.org/10.2298/sjee0603149p.
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In this paper, an overview of the field of wireless powering is presented with an emphasis on low-power applications. Several rectenna elements and arrays are discussed in more detail: (1) a 10-GHz array for powering sensors in aircraft wings; (2) a single antenna in the 2.4-GHz ISM band for low-power assisted-living sensors; and (3) a broadband array for power harvesting in the 2-18GHz frequency range.
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Alsoufi, Bahaaldin, Courtney McCracken, Lazaros K. Kochilas, Martha Clabby und Kirk Kanter. „Factors Associated With Interstage Mortality Following Neonatal Single Ventricle Palliation“. World Journal for Pediatric and Congenital Heart Surgery 9, Nr. 6 (15.10.2018): 616–23. http://dx.doi.org/10.1177/2150135118787723.
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Background: Several advances have led to improved hospital survival following neonatal palliation (NP) of single ventricle (SV) anomalies. Nonetheless, a number of patients continue to suffer from interstage mortality (ISM) prior to subsequent Glenn. We aim to study patients’ characteristics and anatomic, surgical, and clinical details associated with ISM. Methods: A total of 453 SV neonates survived to hospital discharge following NP. Competing risk analysis modeled events after NP (Glenn, transplantation, or death) and examined variables associated with ISM. Results: Competing risk analysis showed that one year following NP, 10% of patients had died, 87% had progressed to Glenn, 1% had received heart transplantation, and 2% were alive without subsequent surgery. On multivariable analysis, factors associated with ISM were as follows: weight ≤2.5 kg (hazard ratio, HR = 2.4 [1.2-4.6], P = .013), premature birth ≤36 weeks (HR = 2.0 [1.0-4.0], P = .05), genetic syndromes (HR = 3.2 [1.7-6.1], P < .001), unplanned cardiac reoperation (HR = 2.1 [1.0-4.4], P = .05), and prolonged intensive care unit (ICU) stay >30 days following NP (HR = 2.5 [1.4-4.5], P < .001). Palliative surgery type (shunt, Norwood, band) was not associated with ISM, although aortopulmonary shunt circulation after Norwood was (HR = 5.4 [1.5-19.2] P = .01). Of interest, underlying SV anatomy was not associated with ISM (HR = 1.1 [0.6-2.2], P = .749). Conclusions: In our series, ISM following NP occurred in 10% of hospital survivors. As opposed to hospital death, underlying SV anomaly was not associated with ISM. Conversely, several patient factors (prematurity, low weight, and genetic syndromes) and clinical factors (unplanned reoperation and prolonged ICU stay following NP) were associated with ISM. Vigilant outpatient management that is individualized to specific clinical and social needs, taking into account all associated factors, is warranted to improve survival in high-risk patients.
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Chaturvedi, Divya, und S. Raghavan. „A Triangular-shaped Quarter-mode Substrate Integrated Waveguide based Antenna for WBAN Applications“. Defence Science Journal 68, Nr. 2 (13.03.2018): 190. http://dx.doi.org/10.14429/dsj.68.11833.
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<p class="Abstract">In this study, a compact quarter-mode substrate integrated waveguide (QMSIW) based dual-band antenna is proposed for wireless body area network applications. A QMSIW resonator is realised by splitting the full-mode substrate integrated waveguide cavity along the perfect magnetic conductor walls. The proposed antenna preserves the fundamental mode TE110 and the third order mode TE220 of the square SIW cavity. The proposed antenna is linearly polarised in the lower band at 2.45 GHz and circularly polarised in the higher frequency band at 5.8 GHz. The on-body performance of the antenna is validated on a piece of pork muscle tissue and it has been found to be stable with respect to surroundings. The proposed antenna covers the ISM bands 44 MHz (2.445 GHz - 2.489 GHz) and 225 MHz (5.730 GHz - 5.955 GHz) at 2.45 GHz and 5.8 GHz, respectively. The measured gain of the antenna on pork tissue is 1.87 dBi and 5.5 dBi at two bands. In addition, the specific absorption rate is obtained of 0.65 mW/g and 1.51 mW/g at two bands (wext = 2 mm), averaged over 1 g of muscle with 100mW input power. Moreover, the simulated and experimental results demonstrate a good agreement.</p>
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Ullah, Md, Mohammad Islam, Touhidul Alam und Farhad Ashraf. „Paper-Based Flexible Antenna for Wearable Telemedicine Applications at 2.4 GHz ISM Band“. Sensors 18, Nr. 12 (01.12.2018): 4214. http://dx.doi.org/10.3390/s18124214.
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This paper demonstrates the performance of a potential design of a paper substrate-based flexible antenna for intrabody telemedicine systems in the 2.4 GHz industrial, scientific, and medical radio (ISM) bands. The antenna was fabricated using 0.54 mm thick flexible photo paper and 0.03 mm copper strips as radiating elements. Design and performance analyses of the antenna were performed using Computer Simulation Technology (CST) Microwave Studio software. The antenna performances were investigated based on the reflection coefficient in normal and bent conditions. The total dimensions of the proposed antenna are 40 × 35 × 0.6 mm3. The antenna operates at 2.33–2.53 GHz in the normal condition. More than an 8% fractional bandwidth is expressed by the antenna. Computational analysis was performed at different flexible curvatures by bending the antenna. The minimum fractional bandwidth deviation is 5.04% and the maximum is 24.97%. Moreover, it was mounted on a homogeneous phantom muscle and a four-layer human tissue phantom. Up to a 70% radiation efficiency with a 2 dB gain was achieved by the antenna. Finally, the performance of the antenna with a homogeneous phantom muscle was measured and found reliable for wearable telemedicine applications.
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Mansour, Mohamed, Kamel Sultan und Haruichi Kanaya. „Compact Dual-Band Tapered Open-Ended Slot-Loop Antenna For Energy Harvesting Systems“. Electronics 9, Nr. 9 (28.08.2020): 1394. http://dx.doi.org/10.3390/electronics9091394.
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In this study, a compact dual-band combined loop-slot planar antenna is proposed. (1) Background: multi-function antennas are desired for wireless communication to cover the desired frequency spectrum. (2) Methods: the proposed antenna consists of a semi-rectangular open-ended loop (OEL) operating at the lower frequency band 920 MHz, an open-ended slot (OES) transmission line that provides resonance at the higher band 2.4 GHz, and a feeding port using the asymmetric coplanar strip (ACS) line. The ACS is used to excite the antenna to achieve dual-band performance. The overall dimensions of the fabricated prototype are 32.5 × 53.5 mm2 (0.1λo×0.16λo), where λo represents the free-space wavelength at the lower frequency. (3) Results: from the calculations, the antenna shows two impedance bandwidths (estimated at −10dB) of 30 MHz (920–950 MHz) and 300 MHz (2.2–2.5 GHz) to cover the ISM band (920 MHz) and 2.45 GHz WiFi bands, respectively. Indeed, the antenna has stable radiation patterns and achieves peak measured realized gain of 1.8 dBi in the lower band and 4.2 dBi in the higher band. (4) Conclusion: the antenna shows the merits of low profile structure, single-layer, and low-cost fabrication. The proposed antenna not only achieves incremental increase in radiation efficiency, but also provides a lightweight, and small footprint.
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Do-Duy, Tho, Christopher M. Wright, Takuya Fujiyoshi, Alistair Glasse, Ralf Siebenmorgen, Robert Smith, Bringfried Stecklum und Michael Sterzik. „Crystalline silicate absorption at 11.1 μm: ubiquitous and abundant in embedded YSOs and the interstellar medium“. Monthly Notices of the Royal Astronomical Society 493, Nr. 3 (12.02.2020): 4463–517. http://dx.doi.org/10.1093/mnras/staa396.
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ABSTRACT Utilizing several instruments on 4–8 m telescopes, we have observed a large sample of objects in the mid-infrared (8–13 μm). These comprise a few evolved stars, multiple envelopes of embedded young stellar objects (YSOs) or compact H-II regions, and several sightlines through the interstellar medium (ISM). The latter is where dust resides – and is potentially modified – between its formation in evolved stellar outflows and deposition in molecular clouds. In most objects, we detect not only the well-known 9.7 μm absorption feature of amorphous silicates but also a second absorption band around 11.1 μm whose carrier is attributed to crystalline forsterite. We propose that crystalline silicates are essentially ubiquitous in the ISM and earliest phases of star formation, and are evolutionary precursors to T-Tauri and Herbig stars where such silicates have been commonly found. Modelling shows that in most YSOs, H-II regions and ISM cases, the forsterite mass fraction is between 1 and 2 per cent, suggesting that the younger phases inherit their abundance from the ISM. However, several sources show much stronger features (abundances ≥3 per cent). This suggests that significant processing, perhaps crystallization by thermal annealing, occurs early on in star formation. Most intriguing is the first detection of crystalline silicate in the diffuse ISM. We propose that our observed abundance is consistent with a mass fraction of crystalline silicates of 10–20 per cent injected into the ISM, along with commonly accepted lifetimes against their destruction, but only if cosmic ray-induced amorphization is insignificant over a few Giga years.
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Jones, A. P. „Dust evolution, a global view: II. Top-down branching, nanoparticle fragmentation and the mystery of the diffuse interstellar band carriers“. Royal Society Open Science 3, Nr. 12 (Dezember 2016): 160223. http://dx.doi.org/10.1098/rsos.160223.
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The origin of the diffuse interstellar bands (DIBs), one of the longest-standing mysteries of the interstellar medium (ISM), is explored within the framework of The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS). The likely nature of the DIB carriers and their evolution is here explored within the framework of the structures and sub-structures inherent to doped hydrogenated amorphous carbon grains in the ISM. Based on the natural aromatic-rich moieties (asphaltenes) recovered from coal and oil, the likely structure of their interstellar analogues is investigated within the context of the diffuse band problem. It is here proposed that the top-down evolution of interstellar carbonaceous grains, and, in particular, a-C(:H) nanoparticles, is at the heart of the formation and evolution of the DIB carriers and their associations with small molecules and radicals, such as C 2 , C 3 , CH and CN. It is most probable that the DIBs are carried by dehydrogenated, ionized, hetero-cyclic, olefinic and aromatic-rich moieties that form an integral part of the contiguous structure of hetero-atom-doped hydrogenated amorphous carbon nanoparticles and their daughter fragmentation products. Within this framework, it is proposed that polyene structures in all their variants could be viable DIB carrier candidates.
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Otman, Oulhaj, Naima A. Touhami, Mohamed Aghoutane und Abdelmounaim Belbachir Kchairi. „A New Design of a Wideband Miniature Antenna Array“. International Journal of Electrical and Computer Engineering (IJECE) 7, Nr. 4 (01.08.2017): 1850. http://dx.doi.org/10.11591/ijece.v7i4.pp1850-1857.
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In this work, we present a new configuration of a new miniature microstrip antenna array having a wide frequency band and with a circular polarization. The bandwidth is about 2GHz for a reflection coefficient under -10dB and centered on the ISM ‘Industrial Scientific Medical’ band at 5.8 GHz. To design such array, we have started the design by validating one antenna element at 10 GHz and after that by using the technique of defected ground, we have validated the antenna array in the frequency band [4 GHz -6 GHz] which will permit to miniature the dimensions. The final fabricated antenna array is mounted on an FR4 substrate, the whole area is 102.48 X 31.39 mm<sup>2</sup> with a gain of 5dBi at 4GHz.
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Silva Júnior, Paulo Fernandes, Ewaldo Santana, Mauro Sergio Silva Pinto, Alexandre Serres, Camila Caroline Rodrigues De Albuquerque und Raimundo Freire. „Bio-Inspired On-Chip Antenna Array for ISM Band60 GHz Application“. Journal of Integrated Circuits and Systems 14, Nr. 2 (25.08.2019): 1–5. http://dx.doi.org/10.29292/jics.v14i2.53.
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A flower-shape bio-inspired aperture-coupled antenna array for on-chip application, generated by Gielis formula, operating in industrial, scientific and medical (ISM) band at 60 GHz (57 GHZ to 64 GHz) is presented in this paper. The antenna proposed is composed of a transmission feed line followed by an aperture and patch element built in aluminum, with 2 micrometers of thickness, lying on two layers of silicon with 200 micrometers of thickness each. Dimensions of the antennas were calculated according to the effective wavelength for the resonance frequency at 60 GHz. Simulations were performed in the commercial software ANSYS® Electronics Desktop. The use of the bio-inspired flower-shape promotes more compact structures with greater perimeter, rearranging these shapes into an antenna array provided a gain and a bandwidth increase in the design, 3.11dBi and 2.86GHz, respectively, which resulted in a maximum gain of 8.82 dBi and a total bandwidth of 5.88 GHz.
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Takagi, Toshinobu, Hideo Matsuhara, Takehiko Wada und Youichi Ohyama. „Photometric studies of PAH emission from distant infrared galaxies“. Proceedings of the International Astronomical Union 7, S284 (September 2011): 456–59. http://dx.doi.org/10.1017/s1743921312009611.
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AbstractUsing extensive mid-IR datasets from AKARI, i.e. 9 band photometry covering the wavelength range from 2 μm to 24 μm and the unbiased spectroscopic survey for sources with Sν (9μm)>0.3 mJy, we investigated the PAHs emission features in distant starburst galaxies. PAH-selected galaxies, selected with an extremely red mid-IR colour due to PAHs, are found to have a peculiar rest-frame 11-to-8 μm flux ratio, which is systematically smaller than nearby starburst/AGN spectral templates. This may indicate a systematic difference in the physical condition of the ISM between nearby and distant starburst galaxies.
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Okba, Abderrahim, Dominique Henry, Alexandru Takacs und Hervé Aubert. „Autonomous RFID Sensor Node Using a Single ISM Band for Both Wireless Power Transfer and Data Communication“. Sensors 19, Nr. 15 (29.07.2019): 3330. http://dx.doi.org/10.3390/s19153330.
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This paper addresses the implementation of autonomous radiofrequency identification sensor nodes based on wireless power transfer. For size reduction, a switching method is proposed in order to use the same frequency band for both supplying power to the nodes and wirelessly transmitting the nodes’ data. A rectenna harvests the electromagnetic energy delivered by the dedicated radiofrequency source for charging a few-mF supercapacitor. For supercapacitors of 7 mF, it is shown that the proposed autonomous sensor nodes were able to wirelessly communicate with the reader at 868 MHz for 10 min without interruption for a tag-to-reader separation distance of 1 meter. This result was obtained from effective radiated powers of 2 W during the supercapacitor charging and of 100 mW during the wireless data communication.
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Zaki, Ahmed Z. A., Tamer Gaber Abouelnaga, Ehab K. I. Hamad und Hala A. Elsadek. „Design of dual-band implanted patch antenna system for bio-medical applications“. Journal of Electrical Engineering 72, Nr. 4 (01.08.2021): 240–48. http://dx.doi.org/10.2478/jee-2021-0033.
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Abstract In this paper, a miniaturized implantable antenna system for biomedical applications is presented. The system consists of almost two similar patch antennas, named internal and external. The internal antenna is implanted inside the body at a depth of 2 mm, and the external antenna is to be attached to the body aligned with the internal one. The antenna system consists of implant-side antenna with dimensions are 10.25×10.25×1.27 mm3 , while the external antenna dimensions are 11.1×11.1×1.27 mm3. The proposed antennas designs showed dual resonant frequency on ISM bands (ie , 915 MHz and 2450 MHz ). The computed -10 dB bandwidth considering three-layer human phantom demonstrates that a bandwidth of 870 to 970 MHz and 2.38 to 2.47 GHz for internal and external antennas are achieved. The Specific Absorption Rate (SAR) has been considered for health care consideration. The measured and simulated scattering parameters are compared, and good agreements are achieved. The proposed antenna system is simulated and investigated for biomedical applications suitability.
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Nuth, Joseph A. „Metamorphism of Cosmic Dust: Diagnostic Infrared Signatures“. Symposium - International Astronomical Union 150 (1992): 39–40. http://dx.doi.org/10.1017/s0074180900089683.
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Nucleation is a non-equilibrium process: the products of this process are seldom the most thermodynamically stable condensates but are instead those which form fastest. It should not be surprising that grains formed in a circumstellar outflow will undergo some degree of metamorphism if they are annealed or exposed to a chemically active reagent. As a consequence of this processing in the laboratory one observes a continuous increase in the strength of the silicate absorption band at 20 microns relative to the 10 micron feature. In Section 1 we show that this ratio can be used as an indicator of the relative age of silicate condensates. Metamorphism of refractory particles continues in the interstellar medium (ISM) where the driving forces are sputtering by cosmic ray particles, annealing by high energy photons and grain destruction in supernova generated shocks. Studies of the depletion of the elements from the gas phase of the ISM tell us that if grain destruction occurs with high efficiency, then there must be some mechanism by which grains can be formed in the ISM. Laboratory studies of such a process (Moore, Tanabe, and Nuth, Ap. J. (Lett) 373, L31-L34, 1990) have shown that the frequency of the -SiH stretch can be used as an indicator of the oxidation state of the silicon in such grains. Highly reduced grains exhibit an SiH absorption near 2100 cm−1 whereas highly oxidized silicates absorb near 2300 cm−1: this point is discussed in Section 2.
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Haghighitalab, Delaram, Diomadson Belfort, Alp Kiliç, Aziz Benlarbi-Delaï und Hassan Aboushady. „A 2.4 GHz ISM-band highly digitized receiver based on a variable gain LNA and a subsampled $$\varSigma \varDelta$$ Σ Δ ADC“. Analog Integrated Circuits and Signal Processing 95, Nr. 2 (03.03.2018): 259–70. http://dx.doi.org/10.1007/s10470-018-1136-2.
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Hampel, S. K., O. Schmitz und I. Rolfes. „Sievenpiper HIS and its influence on antenna correlation“. Advances in Radio Science 6 (26.05.2008): 39–44. http://dx.doi.org/10.5194/ars-6-39-2008.
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Abstract. \\label{sec:abstract} This paper deals with the influence of artificial magnetic conductors (AMC), so-called Sievenpiper High Impedance Surfaces (HIS), on the MIMO and Diversity performance of a planar linear-polarized 2×2 dipole array in the ISM-band at 2.45 GHz. The characteristic performance criteria such as envelope correlation coefficient, spectral efficiency, Mean Effective Gain (MEG) and Diversity gain of a coupled 2×2 dipole array are investigated. By means of full-wave electromagnetic analysis as well as Monte-Carlo simulations applying statistical channel models the characteristic antenna pattern just as the MIMO and Diversity analysis is performed, respectively. The obtained results show that the application of Sievenpiper High Impedance Surfaces to planar antenna arrays enables good MIMO and Diversity performance compared to ideal configurations in free-space while offering the design of low profile antennas with simultaneously enhanced characteristics.
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Scoville, Nick. „ALMA: HI and He+ Lines and Dust in Starbursts, AGN and High-z Galaxies“. Proceedings of the International Astronomical Union 9, S304 (Oktober 2013): 173–79. http://dx.doi.org/10.1017/s1743921314003706.
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AbstractWe describe preliminary results for two ALMA projects – 1) imaging the HCN(4-3) line and H26α lines in Arp 220 and 2) measurements of the dust continuum in a sample of 107 high redshift galaxies to probe the evolution of the ISM masses. The HCN observations in Arp 220 at 1/2″ resolution provide the first high resolution imaging of the dense star forming gas in this prototypical ULIRG. The HCN is seen in two clearly delineated, counter-rotating disks. The H26α line is a definitive probe of the star formation rate in Arp 220, avoiding obscuration by dust and contamination by AGN luminosity contributions. In the second project, the remarkable continuum sensitivity of ALMA in Band 7 is used to measure the long wavelength Rayleigh-Jeans tail of the dust emission from a sample of 120 galaxies in COSMOS at z = 0.3 to 2.2, providing estimates for the dust masses and hence their ISM masses. This technique will enable measurements for hundreds of galaxies at high-z with observations of typically ~10 min per galaxy. This is in contrast to CO line imaging which typically requires a few hours per galaxy even with the sensitivity of ALMA. The dust-based mass estimates also avoid the uncertainties associated with the CO-to-H2 conversion factor.
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Shah, S. M., A. A. Rosman, M. A. Z. A. Rashid, Z. Z. Abidin, F. C. Seman, H. A. Majid, S. H. Dahlan et al. „A compact dual-band semi-flexible antenna at 2.45 GHz and 5.8 GHz for wearable applications“. Bulletin of Electrical Engineering and Informatics 10, Nr. 3 (01.06.2021): 1739–46. http://dx.doi.org/10.11591/eei.v10i3.2262.
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In this work, a compact dual-band semi-flexible antenna operating at 2.45 GHz and 5.8 GHz for the industrial, scientific and medical (ISM) band is presented. The antenna is fabricated on a semi-flexible substrate material, Rogers Duroid RO3003™ with a low-profile feature with dimensions of 30×38 mm2 which makes it a good solution for wearable applications. Bending investigation is also performed over a vacuum cylinder and the diameters are varied at 50 mm, 80 mm and 100 mm, that represents the average human arm’s diameter. The bending investigation shows that reflection coefficients for all diameters are almost similar which imply that the antenna will operate at the dual-band resonant frequencies, even in bending condition. The simulated specific absorption rate (SAR) in CST MWS® software shows that the antenna obeys the FCC and ICNIRP guidelines for 1 mW of input power. The SAR limits at 2.45 GHz for 1 g of human tissue is simulated at 0.271 W/kg (FCC standard: 1.6 W/kg) while for 10 g is at 0.0551 W/kg (ICNIRP standard: 2 W/kg. On the other hand, the SAR limits at 5.8 GHz are computed at 0.202 W/kg for 1 g and 0.0532 W/kg for 10 g.
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Kumar, A. Pramod. „Design of Multiband E-Shaped Patch Antenna with Hexagonal Slot for WLAN Applications“. Carpathian Journal of Electronic and Computer Engineering 12, Nr. 1 (01.09.2019): 37–41. http://dx.doi.org/10.2478/cjece-2019-0007.
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Abstract The objective of E-shaped patch antenna with hexagonal slot is to operate in the ISM band for different kind of applications, such as WLAN, GPS, and various modern wireless systems. The posit antenna is designed using FR4 substrate having a dielectric constant of 4.4 with a thickness of 1.6 mm. Probe feed technique is used for this antenna design. A parametric study was included to determine the effect of design approaches and the antenna performance. The realization of the designed antenna was analyzed in term of boost (gain), return loss, and radiation pattern. The design was upsurged to confirm the best achievable result. This antenna resonates at three different frequencies at 1.6 GHz, 3.24 GHz, and 5.6 GHz with a reflection coefficient less than -10 dB and VSWR<2.
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Huang, Shaomin, Zhongpan Yang und Chao Hua. „A 1.4mW 900MHz LNA with Noise-Canceling Technique in 130nm CMOS Process“. Journal of Circuits, Systems and Computers 27, Nr. 01 (23.08.2017): 1850003. http://dx.doi.org/10.1142/s0218126618500032.
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A noise-canceling low noise amplifier (LNA) structure is proposed in this paper. The LNA works in the 900[Formula: see text]MHz ISM band. The techniques of noise canceling and current-reusing are proposed to improve the noise performance and reduce the power dissipation. The noise cancellation schema is realized by mutually canceling the noise currents of the common-source and common-gate amplifiers. A prototype of the LNA is designed and fabricated in a standard 130[Formula: see text]nm CMOS process. Measurement results under a 1.2[Formula: see text]V supply voltage show that the proposed LNA achieves a voltage gain of 18[Formula: see text]dB and a noise figure of 2[Formula: see text]dB. The whole circuit only consumes a power dissipation of 1.4[Formula: see text]mW.
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Streifinger, M., T. Müller, J. F. Luy und E. M. Biebl. „A software-radio front-end for microwave applications“. Advances in Radio Science 1 (05.05.2003): 201–5. http://dx.doi.org/10.5194/ars-1-201-2003.
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Abstract. In modern communication, sensor and signal processing systems digitisation methods are gaining importance. They allow for building software configurable systems and provide better stability and reproducibility. Moreover digital front-ends cover a wider range of applications and have better performance compared with analog ones. The quest for new architectures in radio frequency front-ends is a clear consequence of the ever increasing number of different standards and the resulting task to provide a platform which covers as many standards as possible. At microwave frequencies, in particular at frequencies beyond 10 GHz, no direct sampling receivers are available yet. A look at the roadmap of the development of commercial analog-to-digital-converters (ADC) shows clearly, that they can neither be expected in near future. We present a novel architecture, which is capable of direct sampling of band-limited signals at frequencies beyond 10 GHz by means of an over-sampling technique. The wellknown Nyquist criterion states that wide-band digitisation of an RF-signal with a maximum frequency ƒ requires a minimum sampling rate of 2 · ƒ . But for a band-limited signal of bandwidth B the demands for the minimum sampling rate of the ADC relax to the value 2 · B. Employing a noise-forming sigma-delta ADC architecture even with a 1-bit-ADC a signal-to-noise ratio sufficient for many applications can be achieved. The key component of this architecture is the sample-and-hold switch. The required bandwidth of this switch must be well above 2 · ƒ . We designed, fabricated and characterized a preliminary demonstrator for the ISM-band at 2.4 GHz employing silicon Schottky diodes as a switch and SiGe-based MMICs as impedance transformers and comparators. Simulated and measured results will be presented.
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Liang, Lichen, Robert Feldmann, Dušan Kereš, Nick Z. Scoville, Christopher C. Hayward, Claude-André Faucher-Giguère, Corentin Schreiber, Xiangcheng Ma, Philip F. Hopkins und Eliot Quataert. „On the dust temperatures of high-redshift galaxies“. Monthly Notices of the Royal Astronomical Society 489, Nr. 1 (02.08.2019): 1397–422. http://dx.doi.org/10.1093/mnras/stz2134.
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Abstract Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading to different physical interpretations of how ISM conditions change with, e.g. redshift and star formation rate. In this paper, we analyse the dust temperatures of massive ($M_{\rm star} \gt 10^{10}\, \mathrm{M}_{\odot }$) $z$ = 2–6 galaxies with the help of high-resolution cosmological simulations from the Feedback in Realistic Environments (fire) project. At $z$ ∼ 2, our simulations successfully predict dust temperatures in good agreement with observations. We find that dust temperatures based on the peak emission wavelength increase with redshift, in line with the higher star formation activity at higher redshift, and are strongly correlated with the specific star formation rate. In contrast, the mass-weighted dust temperature, which is required to accurately estimate the total dust mass, does not strongly evolve with redshift over $z$ = 2–6 at fixed IR luminosity but is tightly correlated with LIR at fixed $z$. We also analyse an ‘equivalent’ dust temperature for converting (sub)millimetre flux density to total IR luminosity, and provide a fitting formula as a function of redshift and dust-to-metal ratio. We find that galaxies of higher equivalent (or higher peak) dust temperature (‘warmer dust’) do not necessarily have higher mass-weighted temperatures. A ‘two-phase’ picture for interstellar dust can explain the different scaling relations of the various dust temperatures.
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Tirkey, Snehlata, P. Mukhopadhyay, R. Phani Murali Krishna, Ashish Dhakate und Kiran Salunke. „Simulations of Monsoon Intraseasonal Oscillation Using Climate Forecast System Version 2: Insight for Horizontal Resolution and Moist Processes Parameterization“. Atmosphere 10, Nr. 8 (26.07.2019): 429. http://dx.doi.org/10.3390/atmos10080429.
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In the present study, we analyze the Climate Forecast System version 2 (CFSv2) model in three resolutions, T62, T126, and T382. We evaluated the performance of all three resolutions of CFSv2 in simulating the Monsoon Intraseasonal Oscillation (MISO) of the Indian summer monsoon (ISM) by analyzing a suite of dynamic and thermodynamic parameters. Results reveal a slower northward propagation of MISO in all models with the characteristic northwest–southeast tilted rain band missing over India. The anomalous moisture convergence and vorticity were collocated with the convection center instead of being northwards. This affected the northward propagation of MISO. The easterly shear to the north of the equator was better simulated by the coarser resolution models than CFS T382. The low level specific humidity showed improvement only in CFS T382 until ~15° N. The analyses of the vertical profiles of moisture and its relation to rainfall revealed that all CFSv2 resolutions had a lower level of moisture in the lower level (< 850 hPa) and a drier level above. This eventually hampered the growth of deep convection in the model. These model shortcomings indicate a possible need of improvement in moist process parameterization in the model in tune with the increase in resolution.
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M. Shah, S., N. F. A. Kadir, Z. Z. Abidin, F. C. Seman, S. A. Hamzah und N. Katiran. „A 2.45 GHz Semi-Flexible wearable antenna for industrial, scientific and medical band applications“. Indonesian Journal of Electrical Engineering and Computer Science 15, Nr. 2 (01.08.2019): 814. http://dx.doi.org/10.11591/ijeecs.v15.i2.pp814-822.
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<span>In this work, a compact size, wearable microstrip patch antenna is designed, simulated and fabricated for the Industrial, Scientific and Medical (ISM) band applications with the operating frequency at 2.45 GHz. A semi-flexible substrate material which is Rogers Duroid RO3003™ with a relative dielectric constant, ε_r of 3, loss tangent, tan δ of 0.010 and thickness, h of 1.52 mm has been proposed to ensure it can be worn on clothes. The antenna has a low-profile feature with 24 × 28 mm2 in dimension. Investigation of the antenna under bending condition on the approximate human arm size is also performed and analysed to ensure that the wearable antenna is applicable for on-body. The bending investigation shows that the initial resonant frequency of 2.45 GHz is shifted to 2.3 GHz. However, the reflection coefficient at 2.45 GHz is still greater than the -10-dB which implies that the antenna is still functional at that particular frequency. The Specific Absorption Rate (SAR) of the antenna has also been simulated to examine whether the antenna obeys the SAR limits under the FCC and CNIRP guidelines. The SAR values obtained show that the antenna obeys the standard for 1 mW input power. The SAR value for 1g of human tissue is computed at 0.03999 W/kg (FCC standard: 1.6 W/kg) while for 10g is at 0.01936W/kg (CNIRP standard: 2 W/kg).</span>
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Moreira e Silva, Paulo M., und Fernando Rangel de Sousa. „Design, Analysis and Measurement Results of a Fully-Integrated Low-power LNA Presenting Faults“. Journal of Integrated Circuits and Systems 8, Nr. 1 (27.12.2013): 32–42. http://dx.doi.org/10.29292/jics.v8i1.370.
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We present in this paper the analysis, design and measurement results of a low noise amplifier (LNA) operating in the ISM band at 2.45 GHz. The circuit topology adopted was based on a current reuse technique to minimize the power consumption. A prototype was fabricated in a 0.18-μm standard CMOS technology and the measured power consumption was 1.1 mW. The measured input reflection coefficient was below -10 dB and the reverse isolation was higher than 20 dB. The measured insertion gain and noise figure were 5.6 dB and 4.8 dB respectively, with divergences from the simulated values of 5 dB and 2 dB, respectively. To explain these discrepancies, we devised an analysis on the circuit, including sources of uncertainties. Moreover, we characterized a transistor included in the LNA die, that helped to explain part of the disagreements. After including the uncertainty sources, we wereaable to explain a deviation of 3.9 dB in the insertion gain with respect to the simulated result.
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Ullah, Shahid, Cunjun Ruan, Muhammad Shahzad Sadiq, Tanveer Ul Haq, Ayesha Kosar Fahad und Wenlong He. „Super Wide Band, Defected Ground Structure (DGS), and Stepped Meander Line Antenna for WLAN/ISM/WiMAX/UWB and other Wireless Communication Applications“. Sensors 20, Nr. 6 (20.03.2020): 1735. http://dx.doi.org/10.3390/s20061735.
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This paper presents a new shape (s-shape monopole) of a super wideband antenna using stepped meander lines, a quarter waveguide transformer feeding line, and a defected ground structure (DGS). The antenna will be used for multiple wireless communication applications like WIMAX/WLAN/ISM/UWB, and also for several wireless communication applications. The total dimensions of the proposed antenna are 35 mm × 35 mm × 1.57 mm or 0.36 λo × 0.36 λo × 0.016 λo, which are the corresponding electrical dimensions with free-space wavelength (λo) at the lower operating frequency. The antenna is designed and simulated into two steps: the first (Antenna 1) covers a bandwidth of 18.2 GHz, while the second (Antenna 2, using DGS) covers a super wide bandwidth of 37.82 GHz (3.08–40.9 GHz). The measured fractional bandwidth and bandwidth ratio of the antenna are 174.68% and 13.009:1, respectively, which is operating from 3.09–40.2 GHz. The maximum calculated gain and efficiency are 5.9 dBi and 92.7%, respectively. The time-domain performance is good due to the calculation of the system fidelity factor, group delay, and its linear and constant phase variation.
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Wang, Yong, Ranran Zhou, Zhenyue Liu und Bingbo Yan. „A Low-Power CMOS Wireless Acoustic Sensing Platform for Remote Surveillance Applications“. Sensors 20, Nr. 1 (28.12.2019): 178. http://dx.doi.org/10.3390/s20010178.
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A low-power wireless acoustic sensing platform for remote surveillance applications based on a 180 nm CMOS technology is proposed in this paper. The audio signal, which is acquired by a microphone, is first amplified and filtered. Then, the analog signal is converted to a digital signal by a 10-bit analog-to-digital converter (ADC). A digital automatic gain control module is integrated to obtain an optimal input of the ADC. The digital signal is modulated and transmitted at the 433 MHz ISM band after being repacked and encoded. To save power for portable applications, the chip switches to standby mode when no audio is detected. The wireless sensing platform occupies a chip area of 1.76 mm 2 . The supply voltage is 2.5 V for the power amplifier and 1.8 V for other circuits. The measured maximum output power is 5.7 dBm and the transmission distance is over 500 m for real application scenarios. The chip consumes 25.1 mW power in normal work mode and 0.058 mW in standby mode. Compared to existing wireless acoustic sensors, the proposed wireless acoustic sensing platform can achieve features such as compactness, power efficiency, and reliability.
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Cassata, P., L. Morselli, A. Faisst, M. Ginolfi, M. Béthermin, P. Capak, O. Le Fèvre et al. „The ALPINE-ALMA [CII] survey“. Astronomy & Astrophysics 643 (27.10.2020): A6. http://dx.doi.org/10.1051/0004-6361/202037517.
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Context. The Lyman-α line in the ultraviolet (UV) and the [CII] line in the far-infrared (FIR) are widely used tools to identify galaxies in the early Universe and to obtain insights into interstellar medium (ISM) properties in high-redshift galaxies. By combining data obtained with ALMA in band 7 at ∼320 GHz as part of the ALMA Large Program to INvestigate [CII] at Early Times (ALPINE) with spectroscopic data from DEIMOS at the Keck Observatory, VIMOS and FORS2 at the Very Large Telescope, we assembled a unique sample of 53 main-sequence star-forming galaxies at 4.4 < z < 6 in which we detect both the Lyman-α line in the UV and the [CII] line in the FIR. Aims. The goal of this paper is to constrain the properties of the Lyα emission in these galaxies in relation to other properties of the ISM. Methods. We used [CII], observed with ALMA, as a tracer of the systemic velocity of the galaxies, and we exploited the available optical spectroscopy to obtain the Lyα-[CII] and ISM-[CII] velocity offsets. Results. We find that 90% of the selected objects have Lyα-[CII] velocity offsets in the range 0 < ΔvLyα − [CII] < 400 km s−1, in line with the few measurements available so far in the early Universe, and significantly smaller than those observed at lower redshifts. At the same time, we observe ISM-[CII] offsets in the range −500 < ΔvISM−[CII] < 0 km s−1, in line with values at all redshifts, which we interpret as evidence for outflows in these galaxies. We find significant anticorrelations between ΔvLyα−[CII] and the Lyα rest-frame equivalent width EW0(Lyα) (or equivalently, the Lyα escape fraction fesc(Lyα)): galaxies that show smaller ΔvLyα−[CII] have larger EW0(Lyα) and fesc(Lyα). Conclusions. We interpret these results in the framework of available models for the radiative transfer of Lyα photons. According to the models, the escape of Lyα photons would be favored in galaxies with high outflow velocities, producing large EW0(Lyα) and small ΔvLyα-[CII], in agreement with our observations. The uniform shell model would also predict that the Lyα escape in galaxies with slow outflows (0 < vout < 300 km s−1) is mainly determined by the neutral hydrogen column density (NHI) along the line of sight, while the alternative model by Steidel et al. (2010, ApJ, 717, 289) would more highly favor a combination of NHI at the systemic velocity and covering fraction as driver of the Lyα escape. We suggest that the increase in Lyα escape that is observed in the literature between z ∼ 2 and z ∼ 6 is not due to a higher incidence of fast outflows at high redshift, but rather to a decrease in average NHI along the line of sight, or alternatively, a decrease in HI covering fraction.
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Hamza, Aven Rawf, und Asaad M. Jassim Al-Hindawi. „The Effecting of Human Body on Slotted Monopole Antenna in Wearable Communications“. Journal of Engineering 27, Nr. 2 (01.02.2021): 27–43. http://dx.doi.org/10.31026/j.eng.2021.02.03.
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In this paper, the characteristics of microstrip monopole antennas are studied firstly in free space. Secondly, the effects of the human body on the studied antenna's performance are investigated for wearable communications. Different patch shapes of microstrip monopole antenna are chosen to operate at two bands: industrial scientific and medical band (ISM) and ultra-wideband (UWB) for wearable applications. The studied antenna consists of a radiating element on one side of the substrate and a partial ground plane on the other side. The antenna is supposed to fabricate on cloth fabric whose relative dielectric constant is Ɛr =1.7. At the same time, the pure copper could be used as the conducting part representing both the radiating monopole and the partial ground plane. The software program of Computer Simulation Technology (CST) for Microwave Studio (MWS) is utilized to simulate the studied antennas. The obtained results have illustrated that in the free space, the proposed antennas of slotted hexagonal, rectangular, and circular shapes can operate from 2-12 GHz and of the bandwidth of 10.31 GHz, 10.19 GHz, and 9.67 GHz, respectively. The hexagonal antenna is selected and proposed to investigate the effects of the human body on its performance. The human body is simulated, and its effects on the performance of the proposed antenna are studied. The reflection coefficient, Voltage Standing Wave Ratio (VSWR), gain, and efficiency are found over that frequency range. The simulated results indicate that the human body effects are significant, and the proposed antenna showed to be a good candidate for wearable communications.
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Mansour, Mohamed M., und Haruichi Kanaya. „Novel L-Slot Matching Circuit Integrated with Circularly Polarized Rectenna for Wireless Energy Harvesting“. Electronics 8, Nr. 6 (10.06.2019): 651. http://dx.doi.org/10.3390/electronics8060651.
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Radio frequency (RF) power harvesting allows wireless power delivery concurrently to several remote RF devices. This manuscript presents the implementation of a compact, reliable, effective, and flexible energy harvesting (EH) rectenna design. It integrates a simple rectifier circuit with a circularly polarized one-sided slot dipole antenna at 2.45 GHz Industrial, Scientific, Medical (ISM) frequency band for wireless charging operation at low incident power densities, from 1 to 95 μ W/cm 2 . The rectenna structure is printed on a single layer, low cost, commercial FR4 substrate. The integration of the rectifier and antenna produces a low-profile and high performance circularly polarized rectenna. In order to maximize the system efficiency, the matching circuit introduced between the rectifier and antenna is optimized for a minimum number of discrete components and it is constructed using multiple of L-slot defects in the ground plane. For a given input power of − 6 dBm intercepted by the circularly polarized antenna with 3 dBi gain, the peak RF-DC (radio frequency-direct current) conversion efficiency is 59.5 % . The rectenna dimensions are 41 × 35.5 mm 2 . It is demonstrated that the output power from the proposed rectenna is higher than the other published designs with a similar antenna size under the same ambient condition. Thanks to its compact size, the proposed rectenna finds a range of potential applications for wireless energy charging.
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Guan, Chai-Eu, und Takafumi Fujimoto. „Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network“. Electronics 9, Nr. 1 (24.12.2019): 21. http://dx.doi.org/10.3390/electronics9010021.
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This paper describes a compact patch antenna intended for medical body area network. The antenna is fed using a proximity coupling scheme to support the antenna that radiates in the free space and on the human body at the 2.45 GHz ISM band. The conductor plane is placed 2 mm or 0.0163λ0 (λ0 is free space wavelength at 2.45 GHz) below the antenna to reduce backward radiation to the human body. Separation distance must be kept above 2 mm, otherwise, gain of the proposed antenna decreases when antenna is situated on the human body. The L-shape feed line is introduced to overcome impedance mismatch caused by the compact structure. The coupling gap between the proposed antenna and the length of the L-shape feed line are optimized to generate dual resonances mode for wide impedance bandwidth. Simulation results show that specific absorption rate (SAR) of the proposed antenna with L-shape feed line is lower than conventional patch antenna with direct microstrip feed line. The proposed antenna achieves impedance bandwidth of 120 MHz (4.89%) at the center frequency of 2.45 GHz. The maximum gain in the broadside direction is 6.2 dBi in simulation and 5.09 dBi in measurement for antenna in the free space. Wide impedance bandwidth and radiation patterns insensitive to the presence of human body are achieved, which meets the requirement of IoT-based wearable sensor.
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Tiwari, N. K., S. P. Singh, D. Mondal und M. Jaleel Akhtar. „Flexible biomedical RF sensors to quantify the purity of medical grade glycerol and glucose concentrations“. International Journal of Microwave and Wireless Technologies 12, Nr. 2 (13.08.2019): 120–30. http://dx.doi.org/10.1017/s1759078719001089.
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AbstractA novel flexible radio frequency (RF) sensor is designed to facilitate the accurate testing of various samples used in the biomedical industry at the industrial, scientific and medical (ISM) frequency band. The proposed RF biosensor comprises a liquid channel-loaded interdigitated capacitor, which is integrated on a coplanar waveguide structure. The prototype of the sensor is fabricated on a 0.13 mm thin biodegradable polyethylene terephthalate polyester film to perform the testing of various bio-graded samples by recording the corresponding resonant frequency. It is observed that there is a noticeable change between the measured resonant frequencies of these samples, which primarily occurs due to the difference in their dielectric properties. The designed sensor was used to monitor and investigate the quality of glycerol, which is the most commonly used raw ingredient in the biomedical and food industry. The determination of glucose concentration in base fluids is considered to ease the challenges faced by doctors and biochemists regarding the monitoring of glucose concentration. It is found that the proposed sensor can quantify the glycerol purity up to the minimum specified adulteration level of 2 and 1% corresponding to toxic contaminants diethylene glycol and ethylene glycol, respectively, and the glucose concentration of 0.5 mg/ml.
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Mansour, Mohamed, Xavier Le Polozec und Haruichi Kanaya. „Enhanced Broadband RF Differential Rectifier Integrated with Archimedean Spiral Antenna for Wireless Energy Harvesting Applications“. Sensors 19, Nr. 3 (05.02.2019): 655. http://dx.doi.org/10.3390/s19030655.
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This work addresses the design and implementation of a broadband differential rectifier (DR) combined with an Archimedean spiral dipole antenna (ASDA) for wireless power harvesting at low incident power densities below 200 μ W/cm 2 . The proposed design exhibits an improved RF-DC conversion efficiency over a wide frequency range from 1.2 to 5 GHz. This frequency band is associated with several wireless communication services, for instance, ISM, WLAN, 5G, LTE, and GPS applications. The receiving planar ASDA exhibits circular polarization and has an average measured gain of 4.5 dBi from 1.2 to 5 GHz. To enable a wide operating bandwidth, the rectifier circuit is constituted by two architectures, designated A and B. Each scheme is designed to harvest power efficiently across a specific bandwidth. The optimal performance of both rectifiers are obtained using the nonlinear harmonic-balance simulations. The antenna–rectifier integration yields a compact rectenna with a high-efficiency performance over the intended bandwidth from 1.2 to 5 GHz for an input power of 9 dBm and terminal load resistance of 1 k Ω . The total measured RF-DC conversion efficiency is maintained above 30% across the entire frequency range with a peak value of 61% achieved at 1.2 GHz. In comparison with similar architectures, the proposed rectenna maintains a stable output efficiency despite the wide fluctuations in the input frequency and also has a minimum footprint size (58 × 55 mm 2 ).