المؤلفون: Takahashi, Yusuke¹ (AUTHOR) ytakahashi@eng.hokudai.ac.jp

المصدر: IEEE Transactions on Aerospace & Electronic Systems. Oct2022, Vol. 58 Issue 5, p4070-4082. 13p.

مصطلحات موضوعية: *DATA transmission systems, RADIO wave propagation, NONEQUILIBRIUM plasmas, DRAG (Aerodynamics), AERODYNAMIC heating, RADIO waves, PLASMA flow, ELECTROMAGNETIC wave propagation

مستخلص: A communication blackout is one of the major problems that occurs during the reentry of a satellite into the Earth's atmosphere, which is caused by the reentry plasma blocking electromagnetic waves near the satellite for telecommunication. Moreover, it prevents tracking and data transmission, resulting in inaccurate prediction of landing sites and data loss. Therefore, there is a necessity to evaluate the propagation of electromagnetic waves in the reentry plasma and to mitigate the communication blackout. An inflatable aeroshell technology with lightweight and large-area features enables aerodynamic drag at high altitudes to reduce aerodynamic heating and to mitigate communication blackouts. Thus, a nanosatellite mission using such an inflatable aeroshell has been proposed. For the purpose of telecommunication possibilities during the reentry in future nanosatellite missions, a detailed investigation of communication blackout mitigation by inflatable aeroshell is required. In the present article, the plasma flow and electromagnetic wave propagation near the nanosatellite during atmospheric reentry were revealed by using a computational science approach. A low-temperature and low-density wake is formed behind the nanosatellite. Moreover, an electromagnetic wave propagation path is formed in the wake, indicating that this path is maintained during the reentry, and no communication blackout occurs when using the deployable nanosatellite. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Aerospace & Electronic Systems is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Sun, Zhi¹ zhisun@ieee.org, Guo, Hongzhi² hguo@nsu.edu, Akyildiz, Ian F.³ ian.akyildiz@tii.ae

المصدر: IEEE Communications Magazine. Oct2022, Vol. 60 Issue 10, p96-102. 7p.

مصطلحات موضوعية: *TELECOMMUNICATION systems, *DATA transmission systems, UNDERWATER acoustic communication, ACOUSTIC wave propagation, EMISSION control, ACOUSTIC transducers, SOUND waves, ACOUSTIC emission testing

مستخلص: Despite decades-long development, underwater communication systems still cannot achieve high data rates and long communication ranges at the same time (i.e., beyond 1 Mb/s and 1 km). Currently, acoustic communication is the only choice to achieve long distances. However, the inherent low acoustic bandwidth results in extremely low data rates. In this article, the acoustic reconfigurable intelligent surface (RIS) system is proposed to realize high-data-rate long-range underwater communications. Although the EM-based RIS has been widely investigated in terrestrial scenarios in recent years, the underwater acoustic RIS is based on completely different physics principles. Hence, the EM-based terrestrial RISs do not work for underwater acoustic signals. More-over, the long acoustic wave propagation delay, the inherent wideband nature, and the water behavior all impose unique challenges in underwater RIS operation. Therefore, this article presents a new hardware design to realize acoustic RIS, based on which the underwater RIS operation protocols are developed to address the aforementioned challenges. The proposed acoustic RIS system can be considered as an underwater infrastructure that enables beamforming functionalities for all types of devices, especially small robots and low-cost sensors. The simulation results show that the proposed acoustic RIS system can efficiently reflect acoustic waves and dramatically increase communication data rates and distances. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Communications Magazine is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Ewe, Wei-Bin¹ ewewb@ihpc.a-star.edu.sg, Koh, Dax Enshan¹ dax_koh@ihpc.a-star.edu.sg, Goh, Siong Thye¹ gohst2@ihpc.a-star.edu.sg, Chu, Hong-Son¹ chuhs@ihpc.a-star.edu.sg, Png, Ching Eng¹ pngce@ihpc.a-star.edu.sg

المصدر: IEEE Transactions on Microwave Theory & Techniques. May2022, Vol. 70 Issue 5, p2517-2525. 9p.

مصطلحات موضوعية: HELMHOLTZ equation, ELECTROMAGNETIC wave propagation, WAVEGUIDES, TRANSMISSION line matrix methods, FINITE difference method, LINEAR equations, LINEAR systems

مستخلص: Variational quantum algorithms (VQAs) are one of the most promising methods that can be implemented on noisy intermediate-scale quantum (NISQ) machines to achieve a quantum advantage over classical computers. This article describes the use of a VQA in conjunction with the finite difference method for the calculation of propagation modes of an electromagnetic wave in a hollow metallic waveguide. The two-dimensional (2-D) waveguide problem, described by the Helmholtz equation, is approximated by a system of linear equations, whose solutions are expressed in terms of simple quantum expectation values that can be evaluated efficiently on quantum hardware. Numerical examples are presented to validate the proposed method for solving 2-D waveguide problems. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Microwave Theory & Techniques is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Zhou, Hang¹ h-zhou@cauc.edu.cn, Chabory, Alexandre¹ chabory@recherche.enac.fr, Douvenot, Remi¹ remi.douvenot@enac.fr

المصدر: IEEE Transactions on Antennas & Propagation. Mar2022, Vol. 70 Issue 3, p2137-2148. 12p.

مصطلحات موضوعية: ELECTROMAGNETIC wave propagation, TROPOSPHERE, DISCRETE wavelet transforms, COMPUTATIONAL complexity, TROPOSPHERIC chemistry, APODIZATION

مستخلص: As an alternative method to the discrete split-step Fourier (DSSF) method, the split-step wavelet method has recently been derived. This method based on a wavelet decomposition of the field is efficient and accurate in simulating the long-range propagation of electromagnetic waves in the low troposphere. In this article, to further improve the computational efficiency and take full advantage of wavelet characteristics, a wavelet-to-wavelet propagation (WWP) method is proposed. The propagation, variable refractivity, and apodization are accounted in the wavelet domain. The computational complexity is reduced, since no transforms are performed between wave fields and wavelet coefficients. This method works well for the propagation over a planar ground with a constant impedance. When a variable impedance ground condition and/or an irregular relief are considered, a hybridization with the split-step wavelet method is proposed. These methods are tested and validated by means of numerical experiments, showing very good efficiency and accuracy. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Antennas & Propagation is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المصدر: IEEE Transactions on Vehicular Technology. Apr2022, Vol. 71 Issue 4, p4428-4437. 10p.

مصطلحات موضوعية: *WIRELESS Internet, RADIO wave propagation

مستخلص: The fine timing measurement (FTM) protocol is designed to determine precise ranging between Wi-Fi devices using round-trip time (RTT) measurements. However, the multipath propagation of radio waves generates inaccurate timing information, degrading the ranging performance. In this study, we use a neural network (NN) to adaptively learn the unique measurement patterns observed at different indoor environments and produce enhanced ranging outputs from raw FTM measurements. Moreover, the NN is trained based on an unsupervised learning framework, using the naturally accumulated sensor data acquired from users accessing location services. Therefore, the effort involved in collecting training data is significantly minimized. The experimental results verified that the collection of unlabeled data for a short duration is sufficient to learn the pattern in raw FTM measurements and produce improved ranging results. The proposed method reduced the errors in raw distance measurements and well-calibrated ranging results requiring the collection of ground truth data by 47–50% and 17–29%, respectively. Consequently, positioning errors were reduced by 17–30% compared to the well-calibrated ranging scenario. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: E. I. Eltahir, Elfatih A. A. Elsheikh, Md. Rafiqul Islam, Aisha H. Abdalla, Mohamed Hadi Habaebi, Alhareth Zyoud, Mosab Hamdan

المصدر: IEEE Access, Vol 12, Pp 79602-79612 (2024)

مصطلحات موضوعية: Sand and dust storm attenuation, micro and millimeter wave propagation, visibility and humidity, complex permittivity, terrestrial communication, Electrical engineering. Electronics. Nuclear engineering, TK1-9971

الوصف: Sand and dust storms present significant challenges to microwave and millimeter-wave propagation, directly impacting communication systems. Despite the existence of various theoretical and analytical models for predicting dust storm attenuation, many have overlooked the crucial factor of humidity. This study had conducted a year-long monitoring of visibility, humidity, and received signal levels for two microwave links operating at 14 GHz and 22 GHz in Khartoum, Sudan. The percentage variation in visibility during a dust storm is 95%, and the percentage variation in humidity is 78%, as the received signal level varies from −42.17 dB to −82 dB. The research unveils a notable correlation between fluctuations in humidity and the complex permittivity of sand and dust particles. Furthermore, this study proposes an empirically developed prediction model for sand and dust storm attenuation, surpassing existing models by incorporating both visibility and humidity data. In contrast to models that solely rely on measured visibility and neglect humidity, this research methodology takes into account both of these measured parameters during dust storms to predict attenuation at any desired frequency. The model’s performance is validated through measurements at 14 GHz, 22 GHz, and 40 GHz, demonstrating robust agreement with the collected data. This comprehensive model provides a more accurate representation of the complex weather conditions during sand and dust storms, enhancing the readability of microwave links design by accurate prediction and mitigation of their impact on communication systems.

وصف الملف: electronic resource

العلاقة: https://ieeexploreTest.ieee.org/document/10547254/; https://doaj.org/toc/2169-3536Test

الوصول الحر: https://doaj.org/article/3a74485315264dbb81d73f1875409c79Test

المؤلفون: Jonas Felix Thomas Theumer, Alenka Zajic

المصدر: IEEE Access, Vol 12, Pp 38298-38303 (2024)

مصطلحات موضوعية: Backscattering, engineering for biology, inference from mm-wave propagation, measurement methodology, Electrical engineering. Electronics. Nuclear engineering, TK1-9971

الوصف: This paper is the first to propose a non-destructive measurement method based on reflection of mm-wave electromagnetic waves from leaves to continuously monitor water content in leaves. We propose to use backscattering, i.e., sending a sweeping sinusoidal signal toward a leaf and measuring the backscattered reflection to estimate water content in a leaf. This method allows for a hand-held device or a drone to perform measurements in the field. The proposed method is agnostic to the type of leaf observed and does not prescribe a required distance from which measurements are taken. Given appropriate transmit power and a suited narrow-beam antenna, this method can be applied at a wide range of distances. The results show that this approach allows for tracking water content in a leaf over time capturing fine grain details, can predict when water is added to the pot, tracks how the plant consumes water over time, and shows the optimal points in time to add more water.

وصف الملف: electronic resource

العلاقة: https://ieeexploreTest.ieee.org/document/10460580/; https://doaj.org/toc/2169-3536Test

الوصول الحر: https://doaj.org/article/75901602b50f4d6e83c87060cc92e981Test

المؤلفون: Alireza Ghorbani, Amir Saman Noor Amin, Ali Abdolali

المصدر: IEEE Access, Vol 12, Pp 11125-11134 (2024)

مصطلحات موضوعية: Electromagnetics, wave propagation, inverse scattering, parameter characterization, deep learning, Electrical engineering. Electronics. Nuclear engineering, TK1-9971

الوصف: This article investigates the extraction of complex refractive indices from the amplitude and phase of the transmitted electric field. In the first step, an incident plane wave has been assumed and the amplitude and phase of the transmitted plane wave is calculated analytically. In this calculation, different values of the complex refractive index have been assumed for the non-magnetic material under test. In fact, the real part and imaginary part of the refractive index are assumed in the range of [1–10] and [0–1], respectively. Furthermore, a general study is made by an assumption of the material thickness to simulation wavelength ratio in the range of [0.01–20]. Due to examining the measurement noise, noisy data are produced for different values of signal-to-noise ratio in the range of [25–40] dB. Due to the difficulties of estimating the refractive index confronted in the theoretical or iterative methods, a Long short-term memory (LSTM) network is proposed and used for the estimation of complex refractive index based on the amplitude and phase of the transmitted electric field. It is shown that the estimation accuracy of about 97% can be achieved in the trained network. Furthermore, the estimation accuracy as a function of thickness-to-wavelength ratio, signal-to-noise ratio, and the values of real and imaginary parts of the refractive index are studied in detail and shown that higher estimation accuracy can be achieved. The simulated results have been confirmed by the measurement for the thickness-to-wavelength ratio below 0.1 and a good agreement has been found. Therefore, the proposed method can replace analytical or repetitive methods as an optimal and more accurate method.

وصف الملف: electronic resource

العلاقة: https://ieeexploreTest.ieee.org/document/10382530/; https://doaj.org/toc/2169-3536Test

الوصول الحر: https://doaj.org/article/ec92cb1db2e44b68a05c346836346ea2Test

المؤلفون: Valdemar Ramon Farre Guijarro, Jose David Vega Sanchez, Martha Cecilia Paredes Paredes, Felipe Grijalva Arevalo, Diana Pamela Moya Osorio

المصدر: IEEE Access, Vol 12, Pp 5708-5730 (2024)

مصطلحات موضوعية: Multiple-input multiple-output (MIMO), 5G New Radio (NR), radio network planning, millimeter-wave (mmWave), wave propagation models, Electrical engineering. Electronics. Nuclear engineering, TK1-9971

الوصف: The 5th-Generation New Radio (5G-NR) network have been widely deployed around the world in the frequency range 1/range 2 bands. Once specific frequency bands within these ranges can vary across different countries and regions due to regulatory differences, it should be carried out radio network planning to evaluate the 5G coverage considering the particularities of different locations. In this regard, this paper performs a throughly analysis of the following methods for modeling wireless channel propagation in Quito, Ecuador: 3rd Generation Partnership Project, Knife Edge Diffraction (KED), ASTER and Dominant Path model (DPM). Specifically, we focus on KED, ASTER, and DPM for $3.5/28$ -GHz bands to determine the propagation models in three-Dimensional urban macro scenarios. In the radio network planning, the multiple-input multiple-output array antennas, $2\times 2/ 4\times 4$ configuration radiation patterns are deployed using WINPROP tool and $64\times 64$ array configuration with the ATOLL tool. 5G frequency specifications, path-loss, influence of diffraction, reflection, blocking, and fading between transmitter and receiver have been considered for scenarios of interest, such as dense urban and urban in Quito, by using fixed wireless access applications and Vehicular-to-Everything (V2X) communications. In addition, data rates, throughput, and the quality metrics of the received reference signal, i.e., the signal-to-noise plus interference ratio, the reference signal received quality, the reference signal received power, and the received signal strength indicator, are also assessed for each propagation model. Finally, we provide useful insights into propagation models and design usage rules for the bands mentioned in 5G networks for Quito city.

وصف الملف: electronic resource

العلاقة: https://ieeexploreTest.ieee.org/document/10381695/; https://doaj.org/toc/2169-3536Test

الوصول الحر: https://doaj.org/article/000d7873e5ab41069eaedcf5fb7a1815Test

المؤلفون: Zhang, Yijie¹ zhangyijie2016@mail.xjtu.edu.cn, Zhao, Haixia² haixia_zhao@mail.xjtu.edu.cn, Yan, Wenjing² wenjingyan@xjtu.edu.cn, Gao, Jinghuai¹ jhgao@mail.xjtu.edu.cn

المصدر: IEEE Transactions on Geoscience & Remote Sensing. Oct2021, Vol. 59 Issue 10, p8228-8240. 13p.

مصطلحات موضوعية: *PETROLEUM prospecting, *NATURAL gas prospecting, ACOUSTIC wave propagation, ANISOTROPY, SEISMIC waves, WAVE equation, ELASTIC waves

مستخلص: For oil and gas exploration, seismic wave propagation in coupled acoustic, elastic, poroelastic, and even anisotropic media is a valuable aspect. However, it is a challenging task to deal with the interfaces of the coupled model. In order to tackle the specific issue, a unified numerical scheme is developed, which is based on the discontinuous Galerkin method. The acoustic, elastic, poroelastic, and anisotropic elastic wave equations are unified into a first-order velocity–stress system. The numerical simulation at the interfaces in the coupled model is conveniently handled by the Godunov flux without any extra operations. Numerical results from the coupled acoustic–elastic and acoustic–poroelastic model are compared with the analytic solutions. In addition, the rates of convergence from different orders are analyzed, which demonstrates the accuracy of the proposed numerical scheme. The surface waves at the fluid–solid interface are studied. Moreover, the proposed scheme is applied to a more complex coupled model, including the coupled acoustic–elastic–poroelastic model and the coupled acoustic–anisotropic elastic model. The corresponding results demonstrate that the proposed numerical scheme is capable of dealing with the coupled model. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Geoscience & Remote Sensing is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)