scholarly journals Atmospheric Propagation Of SubTHz Waves And Space, 6G & 7G Communications

2021 ◽  
Vol 2015 (1) ◽  
pp. 012084
Author(s):  
Lesnov Ilya ◽  
Vdovin Vyacheslav
Keyword(s):  
High Capacity ◽  
Signal Propagation ◽  
Low Noise ◽  
High Signal ◽  
Atmospheric Conditions ◽  
Frequency Range ◽  
Actual Problem ◽  
Atmospheric Propagation ◽  
Data Rates ◽  
Wireless Telecommunication

Abstract The work is devoted to the actual problem of data rate of wireless telecommunication channels. Presented analysis of the telecommunication channel subterahertz (subTHz) frequency range - as the most promising band for the implementation of wireless telecommunications for space links and terrestrial cellular communications of high capacity. A channel considered as a combination of high effective transponder / transmitter duplex together with an open high dissipative atmospheric line. The means to achieve a high signal / noise ratio is usage of low-noise cryogenic receivers. The theoretical analysis of data rates for various atmospheric conditions and technical implementations of communication channels demonstrated reasonable limits of cooling of receivers, providing a weighty increase channel capacity, while deeper cooling is impractical due to weather restrictions in certain ranges and conditions of signal propagation, including altitude and seasonal features.

60 GHz-Band Low-Noise Amplifier

2017 ◽  
Vol 26 (05) ◽  
pp. 1750075 ◽  
Author(s):  
Najam Muhammad Amin ◽  
Lianfeng Shen ◽  
Zhi-Gong Wang ◽  
Muhammad Ovais Akhter ◽  
Muhammad Tariq Afridi
Keyword(s):  
Transmission Line ◽  
Quality Factor ◽  
Noise Figure ◽  
Cmos Technology ◽  
Low Noise ◽  
Constant Current ◽  
60 Ghz ◽  
Frequency Range ◽  
Constant Current Density ◽  
Chip Area

This paper presents the design of a 60[Formula: see text]GHz-band LNA intended for the 63.72–65.88[Formula: see text]GHz frequency range (channel-4 of the 60[Formula: see text]GHz band). The LNA is designed in a 65-nm CMOS technology and the design methodology is based on a constant-current-density biasing scheme. Prior to designing the LNA, a detailed investigation into the transistor and passives performances at millimeter-wave (MMW) frequencies is carried out. It is shown that biasing the transistors for an optimum noise figure performance does not degrade their power gain significantly. Furthermore, three potential inductive transmission line candidates, based on coplanar waveguide (CPW) and microstrip line (MSL) structures, have been considered to realize the MMW interconnects. Electromagnetic (EM) simulations have been performed to design and compare the performances of these inductive lines. It is shown that the inductive quality factor of a CPW-based inductive transmission line ([Formula: see text] is more than 3.4 times higher than its MSL counterpart @ 65[Formula: see text]GHz. A CPW structure, with an optimized ground-equalizing metal strip density to achieve the highest inductive quality factor, is therefore a preferred choice for the design of MMW interconnects, compared to an MSL. The LNA achieves a measured forward gain of [Formula: see text][Formula: see text]dB with good input and output impedance matching of better than [Formula: see text][Formula: see text]dB in the desired frequency range. Covering a chip area of 1256[Formula: see text][Formula: see text]m[Formula: see text]m including the pads, the LNA dissipates a power of only 16.2[Formula: see text]mW.

scholarly journals Detection and localization of multiple small damages in beam

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098732
Author(s):  
Ayisha Nayyar ◽  
Ummul Baneen ◽  
Syed Abbas Zilqurnain Naqvi ◽  
Muhammad Ahsan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
A Priori ◽  
Damage Index ◽  
High Signal ◽  
Frequency Range ◽  
Spatial Locality ◽  
System Frequency

Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known  a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

scholarly journals Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

Analysis of conventional and converted mode reflections at Putah sink, California using three‐component data

Geophysics ◽  
1990 ◽  
Vol 55 (6) ◽  
pp. 646-659 ◽  
Author(s):  
C. Frasier ◽  
D. Winterstein
Keyword(s):  
Time Window ◽  
Structural Features ◽  
Low Noise ◽  
P Wave ◽  
Bright Spot ◽  
High Signal ◽  
Converted Wave ◽  
Gas Field ◽  
Seismic Line ◽  
S Waves

In 1980 Chevron recorded a three‐component seismic line using vertical (V) and transverse (T) motion vibrators over the Putah sink gas field near Davis, California. The purpose was to record the total vector motion of the various reflection types excited by the two sources, with emphasis on converted P‐S reflections. Analysis of the conventional reflection data agreed with results from the Conoco Shear Wave Group Shoot of 1977–1978. For example, the P‐P wave section had gas‐sand bright spots which were absent in the S‐S wave section. Shot profiles from the V vibrators showed strong P‐S converted wave events on the horizontal radial component (R) as expected. To our surprise, shot records from the T vibrators showed S‐P converted wave events on the V component, with low amplitudes but high signal‐to‐noise (S/N) ratios. These S‐P events were likely products of split S‐waves generated in anisotropic subsurface media. Components of these downgoing waves in the plane of incidence were converted to P‐waves on reflection and arrived at receivers in a low‐noise time window ahead of the S‐S waves. The two types of converted waves (P‐S and S‐P) were first stacked by common midpoint (CMP). The unexpected S‐P section was lower in true amplitude but much higher in S/N ratio than the P‐S section. The Winters gas‐sand bright spot was missing on the converted wave sections, mimicking the S‐S reflectivity as expected. CRP gathers were formed by rebinning data by a simple ray‐tracing formula based on the asymmetry of raypaths. CRP stacking improved P‐S and S‐P event resolution relative to CMP stacking and laterally aligned structural features with their counterparts on P and S sections. Thus, the unexpected S‐P data provided us with an extra check for our converted wave data processing.

scholarly journals The millimeter frequency range as a perspective for 5G networks

2019 ◽  
Vol 6 ◽  
pp. 161-170
Author(s):  
Rosen Pasarelski
Keyword(s):  
Mobile Communications ◽  
Spectrum Sharing ◽  
New Technology ◽  
Weather Conditions ◽  
5G Networks ◽  
Frequency Range ◽  
Long Distance ◽  
Data Rates ◽  
Bad Weather ◽  
4G Cellular Networks

The currently widely used 4G cellular networks face many challenges. The growing demand for high-resolution mobile multimedia applications is bringing these networks to their practical limits. 5G networks, the next generation of wireless communications, are standardized to ease the burden on current infrastructure by offering significantly higher data rates through increased channel bandwidth. Given the lack of accessible frequencies traditionally used for mobile communications, millimeter bandwidths (mmWave) are quite a challenging alternative. This technology is a cornerstone of upcoming 5G networks, allowing faster data speeds and much higher bandwidth than ever before, but not every 5G network will necessarily use this frequency band, at least not all the time. As with any new technology, there are unavoidable problems that need to be overcome. The purpose of the research and analysis in this article is to systematize issues and solutions related to the potential problems of spectrum sharing in mmWave frequency range, its suitability for long-distance communications, indoors, in bad weather conditions, as well as biological aspects, and relevant conclusions have been done to meet these challenges.

scholarly journals Latency-Aware Offloading in Integrated Satellite Terrestrial Networks

2020 ◽  
Author(s):  
Wiem Abderrahim ◽  
Osama Amin ◽  
Mohamed-Slim Alouini ◽  
Basem Shihada
Keyword(s):  
Communication Networks ◽  
Rural Areas ◽  
Access Network ◽  
High Capacity ◽  
High Load ◽  
Traffic Load ◽  
Satellite Systems ◽  
High Data ◽  
Data Rates ◽  
Terrestrial Networks

Next-generation communication networks are expected to integrate newly-used technologies in a smart way to ensure continuous connectivity in rural areas and to alleviate the traffic load in dense regions. The prospective access network in 6G should hinge on satellite systems to take advantage of their wide coverage and high capacity. However, adopting satellites in 6G could be hindered because of the {additional latency introduced}, which is not tolerable by all traffic types. Therefore, we propose a traffic offloading scheme that integrates both the satellite and terrestrial networks to smartly allocate the traffic between them while satisfying different traffic requirements. Specifically, the proposed scheme offloads the Ultra-Reliable Low Latency Communication (URLLC) traffic to the terrestrial backhaul to satisfy its stringent latency requirement. However, it offloads the enhanced Mobile Broadband (eMBB) traffic to the satellite since eMBB needs high data rates but is not always sensitive to delay. Our scheme is shown to reduce the transmission delay of URLLC packets, decrease the number of dropped eMBB packets, and hence improve the network's availability. Our findings highlight that the inter-working between satellite and terrestrial networks is crucial to mitigate the expected high load on the limited terrestrial capacity.<br>

Design and Demonstration of 40 micron Bump Pitch Multi-layer RDL on Panel-based Glass Interposers

2015 ◽  
Vol 2015 (1) ◽  
pp. 000379-000385 ◽  
Author(s):  
Brett Sawyer ◽  
Yuya Suzuki ◽  
Zihan Wu ◽  
Hao Lu ◽  
Venky Sundaram ◽  
...  
Keyword(s):  
High Speed ◽  
Metal Layer ◽  
Low Cost ◽  
Signal Propagation ◽  
Additive Process ◽  
Thin Glass ◽  
Fine Pitch ◽  
Data Rates ◽  
Insertion Losses

This paper describes the design, fabrication, and characterization of a two-metal layer RDL structure at 40 um pitch on thin glass interposers. Such an RDL structure is targeted at 2.5D glass interposer packages to achieve up to 1 TB/s die-to-die bandwidth and off-interposer data rates greater than 400 Gb/s, driven by consumer demand of online services for mobile devices. Advanced packaging architectures including 2.5D and 3D interposers require fine line lithography beyond the capabilities of current organic package substrates. Although silicon interposers fabricated using back-end-of-line processes can achieve these RDL wiring densities, they suffer from high electrical loss and high cost. Organic interposers with high wiring densities have also been demonstrated recently using a single sided thin film process. This paper goes beyond silicon and organic interposers in demonstrating fine pitch RDL on glass interposers fabricated by low cost, double sided, and panel-scalable processes. The high modulus and smooth surface of glass helps to achieve lithographic pitch close to that of silicon. Furthermore, the low loss tangent of glass helps in reducing dielectric losses, thus improving high-speed signal propagation. A semi-additive process flow and projection excimer laser ablation was used to fabricate two-metal layer RDL structures and bare glass RDL layers. A minimum of 3 um lithography and 20 um mico-via pitch was achieved. High-frequency characterization of these RDL structures demonstrated single-ended insertion losses of −0.097 dB/mm at f = 1 GHz and differential insertion losses of −0.05 dB/mm at f = 14 GHz.

A Remote Sensing and Atmospheric Correction Method for Assessing Multispectral Radiative Transfer through Realistic Atmospheres and Clouds

2019 ◽  
Vol 36 (2) ◽  
pp. 203-216 ◽  
Author(s):  
Jarred L. Burley ◽  
Steven T. Fiorino ◽  
Brannon J. Elmore ◽  
Jaclyn E. Schmidt
Keyword(s):  
Remote Sensing ◽  
Radiative Transfer ◽  
Performance Metrics ◽  
Meteorological Data ◽  
Weather Prediction ◽  
Atmospheric Correction ◽  
Atmospheric Conditions ◽  
Diffuse Transmission ◽  
Cloud Data ◽  
Atmospheric Propagation

Abstract The ability to quickly and accurately model actual atmospheric conditions is essential to remote sensing analyses. Clouds present a particularly complex challenge, as they cover up to 70% of Earth’s surface, and their highly variable and diverse nature necessitates physics-based modeling. The Laser Environmental Effects Definition and Reference (LEEDR) is a verified and validated atmospheric propagation and radiative transfer code that creates physically realizable vertical and horizontal profiles of meteorological data. Coupled with numerical weather prediction (NWP) model output, LEEDR enables analysis, nowcasts, and forecasts for radiative effects expected for real-world scenarios. A recent development is the inclusion of the U.S. Air Force’s World-Wide Merged Cloud Analysis (WWMCA) cloud data in a new tool set that enables radiance calculations through clouds from UV to radio frequency (RF) wavelengths. This effort details the creation of near-real-time profiles of atmospheric and cloud conditions and the resulting radiative transfer analysis for virtually any wavelength(s) of interest. Calendar year 2015 data are analyzed to establish climatological limits for diffuse transmission in the 300–1300-nm band, and the impacts of various geometry, cloud microphysical, and atmospheric conditions are examined. The results show that 80% of diffuse band transmissions are estimated to fall between 0.248 and 0.889 under the assumptions of cloud homogeneity and maximum overlap and are sufficient for establishing diffuse transmission percentiles. The demonstrated capability provides an efficient way to extend optical wavelength cloud parameters across the spectrum for physics-based multiple-scattering effects modeling through cloudy and clear atmospheres, providing an improvement to atmospheric correction for remote sensing and cloud effects on system performance metrics.

Facile fabrication of microsphere-polymer brush hierarchically three-dimensional (3D) substrates for immunoassays

2015 ◽  
Vol 51 (31) ◽  
pp. 6749-6752 ◽  
Author(s):  
Jiao Ma ◽  
Shifang Luan ◽  
Lingjie Song ◽  
Shuaishuai Yuan ◽  
Shunjie Yan ◽  
...  
Keyword(s):  
Polymer Brush ◽  
Three Dimensional ◽  
Low Noise ◽  
High Signal ◽  
Facile Fabrication

A facile strategy was developed to create a microsphere-polymer brush hierarchically three-dimensional substrate for high signal and low noise in immunoassays.

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