Studying the Impact of Return Current Path on the EM Simulation of High-speed Package Designs

2011 ◽  
Vol 2011 (1) ◽  
pp. 000061-000068
Author(s):  
Darryl Kostka ◽  
Antonio Ciccomancini Scogna
Keyword(s):  
High Speed ◽  
Ground Plane ◽  
Three Dimensional ◽  
Simulation Models ◽  
Current Path ◽  
Cavity Resonances ◽  
Simulation Results ◽  
The Impact ◽  
Simulation Time

Three-dimensional electromagnetic simulation models are often simplified in order to reduce the simulation time and memory requirements without sacrificing the accuracy of the results. A commonly adopted methodology in the simulation of electronic package designs is to truncate the size of the package model leaving only a few important features surrounding the nets of interest. In this paper we demonstrate that this simplification can have a significant impact of the simulation results if it is not performed carefully and it can introduce spurious/non physical resonances. The interaction between cavities and signals is first studied using a simple coupled differential via test structure. It is demonstrated that the return currents generated by these vias excite cavity resonances in power-ground plane pairs causing them to behave as parallel-plate waveguides. The role of interplane shorting vias in suppressing cavity resonances is then investigated and the impact of boundary conditions on the simulation results of package models is also shown and discussed. Finally, a realistic complex multilayer package model is analyzed and it is demonstrate that through proper truncation of the geometry, accurate results can be obtained.

Studying the Impact of Return Current Path on the EM Simulation of High-Speed Package and Board Designs

2012 ◽  
Vol 9 (2) ◽  
pp. 52-64
Author(s):  
Darryl Kostka ◽  
Antonio Ciccomancini Scogna
Keyword(s):  
High Speed ◽  
Ground Plane ◽  
Three Dimensional ◽  
Simulation Models ◽  
Combined Model ◽  
Current Path ◽  
Cavity Resonances ◽  
Simulation Results ◽  
The Impact

Three-dimensional electromagnetic simulation models are often simplified in order to reduce simulation time and memory requirements without sacrificing the accuracy of the results. A commonly adopted methodology in the simulation of complex electronic package and board designs is to truncate the size of the model, leaving only a few important features surrounding the nets of interest. In this paper we demonstrate that this simplification can have a significant impact on the simulation results if it is not performed carefully, and it can introduce spurious nonphysical resonances. The interaction between cavities and signals is first studied using a simple coupled differential via test structure. It is demonstrated that the return currents generated by these vias excite cavity resonances in power-ground plane pairs causing them to behave as parallel-plate waveguides. The role of interplane shorting vias in suppressing cavity resonances is then investigated and the impact of boundary conditions on the simulation results of package models is also shown and discussed. The focus is then shifted to PCB/package cosimulation and the impact of different truncation schemes is discussed through the simulation of test structures of varying complexity. A simulation methodology is then proposed and is verified for a combined model of a realistic complex multilayer package and board and it is demonstrated that accurate results can be obtained through proper truncation of the geometry.

Optimizing electronic standard cell libraries for variability tolerance through the nano-CMOS grid

2010 ◽  
Vol 368 (1925) ◽  
pp. 3967-3981 ◽  
Author(s):  
James Alfred Walker ◽  
Richard Sinnott ◽  
Gordon Stewart ◽  
James A. Hilder ◽  
Andy M. Tyrrell
Keyword(s):  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Circuit Simulation ◽  
Fitness Function ◽  
Three Dimensional ◽  
Simulation Models ◽  
Oxide Semiconductor ◽  
Standard Cell ◽  
The Impact

The project Meeting the Design Challenges of nano-CMOS Electronics ( http://www.nanocmos.ac.uk ) was funded by the Engineering and Physical Sciences Research Council to tackle the challenges facing the electronics industry caused by the decreasing scale of transistor devices, and the inherent variability that this exposes in devices and in the circuits and systems in which they are used. The project has developed a grid-based solution that supports the electronics design process, incorporating usage of large-scale high-performance computing (HPC) resources, data and metadata management and support for fine-grained security to protect commercially sensitive datasets. In this paper, we illustrate how the nano-CMOS (complementary metal oxide semiconductor) grid has been applied to optimize transistor dimensions within a standard cell library. The goal is to extract high-speed and low-power circuits which are more tolerant of the random fluctuations that will be prevalent in future technology nodes. Using statistically enhanced circuit simulation models based on three-dimensional atomistic device simulations, a genetic algorithm is presented that optimizes the device widths within a circuit using a multi-objective fitness function exploiting the nano-CMOS grid. The results show that the impact of threshold voltage variation can be reduced by optimizing transistor widths, and indicate that a similar method could be extended to the optimization of larger circuits.

scholarly journals Preterm Birth Impacts the Timing and Excursion of Oropharyngeal Structures during Infant Feeding

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
C E Edmonds ◽  
E A Catchpole ◽  
F D H Gould ◽  
L E Bond ◽  
B M Stricklen ◽  
...  
Keyword(s):  
Soft Palate ◽  
High Speed ◽  
Neural Control ◽  
Three Dimensional ◽  
Healthy Population ◽  
Term Infants ◽  
Postnatal Maturation ◽  
Pharyngeal Manometry ◽  
The Impact

Synopsis Swallowing in mammals requires the precise coordination of multiple oropharyngeal structures, including the palatopharyngeal arch. During a typical swallow, the activity of the palatopharyngeus muscle produces pharyngeal shortening to assist in producing pressure required to swallow and may initiate epiglottal flipping to protect the airway. Most research on the role of the palatopharyngeal arch in swallowing has used pharyngeal manometry, which measures the relative pressures in the oropharynx, but does not quantify the movements of the structures involved in swallowing. In this study, we assessed palatopharyngeal arch and soft palate function by comparing their movements in a healthy population to a pathophysiological population longitudinally through infancy (term versus preterm pigs). In doing so, we test the impact of birth status, postnatal maturation, and their interaction on swallowing. We tracked the three-dimensional (3D) movements of radiopaque beads implanted into relevant anatomical structures and recorded feeding via biplanar high-speed videofluoroscopy. We then calculated the total 3D excursion of the arch and soft palate, the orientation of arch movement, and the timing of maximal arch constriction during each swallow. Soft palate excursion was greater in term infants at both 7 and 17 days postnatal, whereas arch excursion was largely unaffected by birth status. Maximal arch constriction occurred much earlier in preterm pigs relative to term pigs, a result that was consistent across age. There was no effect of postnatal age on arch or soft palate excursion. Preterm and term infants differed in their orientation of arch movement, which most likely reflects both differences in anatomy and differences in feeding posture. Our results suggest that the timing and coordination of oropharyngeal movements may be more important to feeding performance than the movements of isolated structures, and that differences in the neural control of swallowing and its maturation in preterm and term infants may explain preterm swallowing deficits.

A Dicode Signaling Scheme for Capacitively Coupled Interface

2011 ◽  
Vol 497 ◽  
pp. 296-305
Author(s):  
Yasushi Yuminaka ◽  
Kyohei Kawano
Keyword(s):  
Partial Response ◽  
Data Transmission ◽  
High Speed ◽  
Circuit Simulation ◽  
Frequency Bandwidth ◽  
Capacitively Coupled ◽  
Limited Frequency ◽  
Simulation Results ◽  
Response Coding ◽  
The Impact

In this paper, we present a bandwidth-efficient partial-response signaling scheme for capacitivelycoupled chip-to-chip data transmission to increase data rate. Partial-response coding is knownas a technique that allows high-speed transmission while using a limited frequency bandwidth, by allowingcontrolled intersymbol interference (ISI). Analysis and circuit simulation results are presentedto show the impact of duobinary (1+D) and dicode (1-D) partial-response signaling for capacitivelycoupled interface.

scholarly journals A study about signal variation with minor receiver displacement in a meeting room at 60 GHz: measurements and simulations

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Muhammad Usman Sheikh ◽  
Kalle Ruttik ◽  
Riku Jäntti ◽  
Jyri Hämäläinen
Keyword(s):  
Power Level ◽  
Three Dimensional ◽  
60 Ghz ◽  
System Configuration ◽  
Conference Room ◽  
Channel Characteristics ◽  
Received Power ◽  
Simulation Results ◽  
Small Change ◽  
The Impact

AbstractThe aim of this work is to study the impact of small receiver displacement on a signal propagation in a typical conference room environment at a millimeter wave frequency of 60 GHz. While channel measurements provide insights on the propagation phenomena, their use for the wireless system performance evaluation is challenging. Whereas, carefully executed three-dimensional ray tracing (RT) simulations represent a more flexible option. Nevertheless, a careful validation of simulation methodology is needed. The first target of this article is to highlight the benefits of an in-house built three-dimensional RT tool at 60 GHz and shows the effectiveness of simulations in predicting different characteristics of the channel. To validate the simulation results against the measurements, two different transmitter (Tx) positions and antenna types along with ten receiver (Rx) positions are considered in a typical conference room. In first system configuration, an omnidirectional antenna is placed in the middle of the table, while in the second system configuration a directed horn antenna is located in the corner of the meeting room. After validating the simulation results with the measurement data, in the second part of this work, the impact of a small change, i.e., 20 cm in the receiver position, is studied. To characterize the impact, we apply as performance indicators the received power level, root mean square delay spread (RMS-DS) and RMS angular spread (RMS-AS) in azimuth plane. The channel characteristics are considered with respect to the direct orientation (DO), i.e., the Rx antenna is directed toward the strongest incoming path. Different antenna configurations at the Tx and Rx side are applied to highlight the role of antenna properties on the considered channel characteristics. Especially, in the second system configuration the impact of different antenna half power beamwidth on different considered channel characteristics is highlighted through acquired simulation results. The validation of results shows the RMS error of only 2–3 dB between the measured and simulated received power levels for different Tx configurations in the direction of DO. Results indicate that only a small change of the Rx position may result a large difference in the received power level even in the presence of line-of-sight between the Tx and Rx. It is found that the STD of received power level across the room increases with the decrease in HPBW of the antenna. As can be expected, directed antennas offer lower value of RMS-DS and RMS-AS compared with isotropic antenna.

scholarly journals Wanted: A Revolution in Agriculture

2021 ◽  
pp. 97-122
Author(s):  
Jakkie Cilliers
Keyword(s):  
Food Security ◽  
Foreign Exchange ◽  
Modern Technology ◽  
Access To Finance ◽  
Significant Potential ◽  
Health And Nutrition ◽  
Current Path ◽  
The Impact ◽  
Improve Health

AbstractAgriculture is the backbone of many African economies. Cilliers explores the history and role of agriculture in development, and the likely future trajectory of agriculture in Africa along the Current Path, drawing lessons from other regions. Improvements in this sector, particularly access to finance and use of modern technology can unlock the significant potential to achieve food security, improve health and nutrition outcomes, create agribusiness ventures that influence employment, earn foreign exchange through exports and promote economic prosperity. The chapter concludes with a scenario that emulates the impact of a revolution in agriculture on food security and growth.

A Sociocultural Perspective on Negotiating Digital Identities in a Community of Learners

2013 ◽  
pp. 210-224 ◽  
Author(s):  
Anna Peachey ◽  
Greg Withnail
Keyword(s):  
Social Interaction ◽  
Identity Development ◽  
Three Dimensional ◽  
Digital Identity ◽  
Sociocultural Perspective ◽  
Regular Feature ◽  
Virtual World Environments ◽  
The Impact ◽  
Digital Identities

Three dimensional virtual world environments are becoming an increasingly regular feature of the education landscape, providing the opportunity for richly graphical augmented and immersive learning activities. Those who participate in these experiences must mediate through an avatar, negotiating and managing the complexities of this new variation of digital identity alongside their more familiar identity as learner and/or teacher/facilitator. This chapter describes some key moments in the construction of digital identities as a lecturer and a student in the Open University’s community in Second LifeTM. The authors explore experiences in relation to the impact of trust and consistency from a sociocultural perspective, privileging the role of social interaction and context where meaning is socially produced and situationally interpreted, concluding that social interaction is pivotal to any meaningful identity development that takes place. The chapter ends with thoughts for future issues surrounding digital identity in relation to lifelong learning.

Design and Robustness of Quilt Packaging Superconnect

2012 ◽  
Vol 2012 (1) ◽  
pp. 000524-000530
Author(s):  
M. Ashraf Khan ◽  
Jason M. Kulick ◽  
Alfred M. Kriman ◽  
Gary H. Bernstein
Keyword(s):  
Thermal Cycling ◽  
High Speed ◽  
Low Cycle Fatigue ◽  
Simulation Models ◽  
Electrical Performance ◽  
Cycle Fatigue ◽  
Signal Delay ◽  
Thermal Reliability ◽  
Simulation Results ◽  
Quilt Packaging

Quilt Packaging (QP) is a novel high-speed superconnect (i.e. direct interchip interconnect), developed to improve electrical performance — signal delay, power loss, etc. Ultrahigh bandwidth has already been demonstrated for QP, but its unique structure requires thermal reliability issues to be studied. To this end, simulation models were developed to study the robustness of QP. QP structures were fabricated, and thermal cycling tests were performed focusing on the reliability for various shapes of nodules, the basic physical interconnect unit of QP. Simulations were performed to determine stress over a range of temperatures and estimate low cycle fatigue lifetimes. Simulations considered two types of solder and several adhesives. Thermal cycling experiments indicate that QP provides a robust structure, in agreement with the simulation results.

Theoretical analysis of LC-refining – pressure screening systems in TMP

2019 ◽  
Vol 34 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Jorge Enrique Rubiano Berna ◽  
Christer Sandberg ◽  
Mark Martinez ◽  
James Olson
Keyword(s):  
Fibre Length ◽  
Performance Curves ◽  
Average Fibre ◽  
Mechanical Pulps ◽  
Simulation Results ◽  
Save Energy ◽  
Relative Errors ◽  
The Impact ◽  
Screening Systems

Abstract LC refining of mechanical pulps has proven to save energy in the production of TMP pulps. However, the specific role of LC refining as part of a TMP system has not been thoroughly studied since it is difficult to conceive any particular system at industrial-scales and impractical at pilot-scales. In this study, pressure screening and LC refining models that describe fibre length distributions, together with correlations to predict refining power were used to model three basic refining systems. From the simulation results, the impact of important variables such as reject ratio, refiner gap and refining net-power was studied. Performance curves of length-weighed average fibre length were generated from simulation results and were used to assess each system behaviour and also to make comparisons between systems. Data from an industrial scale TMP mill sub-system was gathered and compared to simulation results showing relative errors between 0–18 % on the predicted variables.

The effect analysis of an engine jet on an aircraft blast deflector

2018 ◽  
Vol 41 (4) ◽  
pp. 990-1001
Author(s):  
Song Ma ◽  
Jianguo Tan ◽  
Xiankai Li ◽  
Jiang Hao
Keyword(s):  
High Temperature ◽  
Flow Field ◽  
High Speed ◽  
Deflection Angle ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Experimental Results ◽  
Exhaust Gases ◽  
The Impact

This paper establishes a novel mathematical model for computing the plume flow field of a carrier-based aircraft engine. Its objective is to study the impact of jet exhaust gases with high temperature, high speed and high pressure on the jet blast deflector. The working condition of the nozzle of a fully powered on engine is first determined. The flow field of the exhaust jet is then numerically simulated at different deflection angle using the three-dimensional Reynolds averaged Navier–Stokes equations and the standard [Formula: see text]-[Formula: see text] turbulence method. Moreover, infra-red temperature tests are further carried out to test the temperature field when the jet blast deflector is at the [Formula: see text] deflection angle. The comparison between the simulation results and the experimental results show that the proposed computation model can perfectly describe the system. There is only 8–10% variation between them. A good verification is achieved. Moreover, the experimental results show that the jet blast deflector plays an outstanding role in driving the high-temperature exhaust gases. It is found that [Formula: see text] may be the best deflection angle to protect the deck and the surrounding equipment effectively. These data results provide a valuable basis for the design and layout optimization of the jet blast deflector and deck.

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