The reduction of broadband crosstalk interference between multiple conductors in a backplane interconnect and its performance impact on gigabit digital communication signals

Crosstalk interference from signal transmission between transmission line conductors limits channel throughput as amplitude distortion in an experimental backplane connector. Shared return conductor microstrip connectors arranged in stacks have resonant frequencies that are determined largely by cavity dimensions of the return conductor geometries. If an input waveform to the connector excites these resonant frequencies, the resonant energy will couple to other signal conductors in the connector and will result in crosstalk interference. Lossy materials can be used to reduce the resonant crosstalk interference in connectors. Quasi-conductor and magnetic absorber materials were used to reduce the resonant crosstalk in an experimental connector. Full-wave computer simulation was used to calculate connector S-parameters and was compared with measurement. Empirical equations were developed to relate experimental S-parameters of connector lossy material configurations with system bit-error-rate, channel Q, and eye pattern height at the data rate of 10.6Gbps

Modeling and estimation of crosstalk across a channel with multiple, non-parallel coupling and crossings of multiple aggressors in practical PCBS

In Section 1, the focus is on alleviating the modeling challenges by breaking the overall geometry into small, unique sections and using either a Full-Wave or fast equivalent per-unit-length (Eq. PUL) resistance, inductance, conductance, capacitance (RLGC) method or a partial element equivalent circuit (PEEC) for the broadside coupled traces that cross at an angle. The simulation challenge is resolved by seamlessly integrating the models into a statistical simulation tool that is able to quantify the eye opening at BERs that would help electrical designers in locating crosstalk sensitive regions in the high speed backplane channel designs. Section 2 investigates the FEXT crosstalk impact on eye opening at a specified bit error rate (BER) at different signal speeds for broadside and edge side differential coupled traces in inhomogeneous media and compared the results against homogeneous media models. A set of design guidelines regarding the material, coupled length and stackup parameter selection is formulated for designers based on the signaling speeds. The major objective of the study in Section 3 is to determine quantitatively the effect of crosstalk due to periodic broadside coupled routing. Another objective is to help designers figure out the “dos” and “don’ts” of broadside coupled routing for higher signaling rates. A new methodology is proposed in Section 4 to generate BER contours that capture the Tx driver jitter and ISI through the channel accurately using unique waveforms created from truth table bit combinations. It utilizes 2N short N bit patterns as waveforms and jitter correlation from current bit pattern into adjacent bit patterns to get equivalent transient simulation of a very large bit pattern. --Abstract, page iii

State of the art in chip-to-chip interconnects

This thesis presents a study of short-range links for chips mounted in the same package, on printed circuit boards or interposers. Implemented in CMOS technology between 7 and 250 nm, with links that operate at a data rate between 0,4 and 112 Gb/s/pin and with energy efficiencies from 0,3 to 67,7 pJ/bit. The links operate on channels with an attenuation lower than 50 dB. A comparison is made with graphical representations between the different articles that shows the correlation between the different essential metrics of chip-to-chip interconnects, as well as its evolution over the last 20 years.Esta tesis presenta un estudio de enlaces de corto alcance para chips montados en un mismo paquete, en placas de circuito impreso o intercaladores. Implementado en tecnología CMOS entre 7 y 250 nm, con enlaces que operan a una velocidad de datos entre 0,4 y 112 Gb/s/pin y con eficiencias energéticas de 0,3 a 67,7 pJ/bit. Los enlaces operan en canales con una atenuación inferior a 50 dB. Se realiza una comparación con representaciones gráficas entre los diferentes artículos que muestra la correlación entre las distintas métricas esenciales de las interconexiones chip a chip, así como su evolución en los últimos 20 años.Aquesta tesi presenta un estudi d'enllaços de curt abast per a xips muntats en el mateix paquet, en plaques de circuits impresos o interposers. Implementat en tecnologia CMOS entre 7 i 250 nm, amb enllaços que funcionen a una velocitat de dades entre 0,4 i 112 Gb/s/pin i amb eficiències energètiques de 0,3 a 67,7 pJ/bit. Els enllaços funcionen en canals amb una atenuació inferior a 50 dB. Es fa una comparació amb representacions gràfiques entre els diferents articles que mostra la correlació entre les diferents mètriques essencials d'interconnexions xip a xip, així com la seva evolució en els darrers 20 anys

Réflectométrie appliquée à la détection de défauts non francs dans les torons de câbles

Ces travaux de thèse portent sur la détection de défauts non francs dans des structures filaires particulières : les lignes de transmission a multiconducteurs (MTL), aussi appelées torons de câbles. Couramment employées pour le diagnostic de réseaux filaires, les méthodes par réflectométrie ne sont, pour l'heure, pas suffisamment performantes pour détecter de tels défauts. Par ailleurs, elles n'ont, en général, été étudiées et développées que pour des lignes simples, ou les phénomènes de couplages électromagnétiques entre les conducteurs (diaphonie) ne sont pas présents. Ces derniers sont cependant porteurs d'information supplémentaire sur l'état du câble. Les utiliser permettrait d'accroître la sensibilité de détection aux défauts. L'objectif est de proposer une nouvelle méthode de réflectométrie, tirant profit des signaux de diaphonie pour détecter les défauts non francs. Une telle méthode présente également l'avantage d'être adaptée aux structures en toron. Après avoir étudié l'impact d'un défaut non franc sur les paramètres caractéristiques d'une MTL et sur les signaux de diaphonie, une méthode, la "Cluster Time Frequency Domain Reflectometry ", a pu être proposée. Il s'agit d'un procédé en trois étapes. Des mesures par réflectométrie temporelle sont tout d'abord réalisées à l'entrée de la ligne à diagnostiquer. Tous les signaux présents, y compris ceux de diaphonie, sont enregistrés. Un traitement temps-fréquence leur est ensuite appliqué afin d'amplifier la présence d'éventuels défauts. Enfin, un algorithme de clustering, spécifiquement développé pour le diagnostic filaire, est utilisé de manière a bénéficier de l'ensemble de l'information disponibleResearch works presented in this thesis rely on detecting soft faults (incipient faults) in specic wiring structures : multiconductor transmission lines (MTL), also known as bundles of wires. Reflectometry methods, often used for the diagnosis of wiring networks, aren't for now efficient enough at detecting such defects. Besides, they have been designed for single lines only, where electromagnetic coupling between conductors (crosstalk) is not to be considered. However such phenomenon can provide more information about the state of the cable. Using this information could enable us to detect soft faults more easily. Our goal is to propose a new reflectometry method, which takes advantage of crosstalk signals in order to detect incipient faults. Such a tool has also the advantage of being well-adapted to bundles of cables. Thanks to the preliminary study of the impact of soft faults on the characteristic parameters of a MTL and on crosstalk signals, a method called "Cluster Time Frequency Domain Reflectometry ", has been proposed. It is a three step process. Firts temporal reflectometry measurements are made at the beginning of the line under test. All the available signals, even crosstalk ones, are recorded. A time-frequency process is then applied on them, in order to amplify the presence of defects. Finally, a clustering algorithm, that has been specically developed for wiring diagnosis, is used to benefit from the whole available informationPARIS-EST-Université (770839901) / SudocSudocFranceF

NASA Tech Briefs, August 1994

Topics covered include: Computer Hardware; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Reports

Development of a composite CAD package to predict and reduce EM radiation from a PCB

A composite CAD package to predict and reduce radiation from a printed circuit board (PCB) is presented in this thesis. The composite CAD package is implemented using an electromagnetic (EM) computation tool linked with other circuit design packages (CDPs) such as ORCAD (a schematic design package), PSPICE (a circuit simulation package) and Boardmaker (a board layout tool). Software is developed to link all the packages so that one can incorporate EMC verification in the design process of an electronic product. The well-known Numerical Electromagnetic Code (NEC) version 2 is used as an EM computation tool. In using NEC-2 to predict PCB radiation, the PCB is simulated as a loaded thin wire structure just above (but not contacting) the surface of an imperfect ground. An algorithm is developed and implemented to automate the geometrical modelling of a wire structure for NEC-2. The data required by NEC-2 ( geometrical, load and electrical) for prediction of PCB radiation can be obtained from various CDPs. The development and implementation of data extraction algorithms are presented in this thesis. Single and double sided PCBs can be accommodated and the work can be extended to handle multilayer PCBs. The use of NEC-2 for this type of application has been validated experimentally and theoretically (by comparing NEC-2 predicted radiation with that obtained where the EM radiation from a pair of parallel PCB tracks running between two components/devices is computed using transmission line modelling-TLM). Both methods of evaluation are described in detail in this thesis and results showing good agreement are presented. TLM is employed by considering, (i) the effective dielectric constant of the medium (air and substrate) surrounding the PCB tracks and (ii) the displacement current between the two PCB tracks. The effect of displacement current in near field radiation is highlighted. The use of TLM for prediction of PCB radiation is verified experimentally. Measured radiation is in good agreement with prediction. In the developed composite CAD package, one can compare the predicted radiation with the mandatory EMC requirement laid down by the regulating bodies and "close the loop" to modify the design where these requirements have not been met. Various techniques to reduce radiation can also be employed. Reduction of radiation by providing shielding in some section of the circuit is proposed. An algorithm is developed and implemented to find the section of the circuit where shielding is necessary. The optimum layout (track separation to width ratio) that can minimise radiation is found theoretically. An optimum layout is also determined experimentally and compared with the theoretical value. A good agreement is found in this comparison. Thus a guideline to choose optimum layout for minimum radiation is provided

ATS-F ground station integration

The ATS ground stations were described, including a system description, operational frequencies and bandwidth, and a discussion of individual subsystems. Each station configuration is described as well as its floor plan. The station performance, as tested by the GSI, is displayed in chart form providing a summary of the more important parameters tested. This chart provides a listing of test data, by site, for comparison purposes. Also included is a description of the ATS-6 experiments, the equipment, and interfaces required to perform these experiments. The ADP subsystem and its role in the experiments is also described. A description of each program task and a summary of the activities performed were then given. These efforts were accomplished at the Rosman II Ground Station, located near Rosman N.C., the Mojave Ground Station, located near Barstow Ca., and the GSI Contractors plant located near Baltimore, Md

Microwave design of multi-layer interposers for the packaging of photonic integrated circuits

The increasing growth of data traffic on the Internet is supported by innovations in high-speed photonic devices. Some of this novel photonic devices are photonic integrated circuits (PICs) that use higher speeds, have higher circuit density and integrate more heterogeneous devices. A new generation of photonic packaging is also required to handle the increasing device density and data rate of the PICs. An important element to package the PICs is the carrier board which also serves as an interposer between the PIC and the package. The usual interposer material for PICs is a single-layer aluminium nitride (AlN) substrate due to its high thermal conductivity and good microwave performance. In contrast, other high-speed and high-density applications use multi-layer substrates as carrier boards. The typical multi-layer technologies for high-speed interposers is low-temperature co-fired ceramic (LTCC). The motivation of this research is the need of multi-layer interposers suitable for the packaging of high-speed and high-density PICs. A key element to enable this multi-layer interposer is the high-speed channels. The task of this research was the microwave design of these high-speed channels for a multi-layer interposer and carrier board suitable for PICs. The main findings of this research can be divided into three areas. First, improvements to the microwave theory. A novel impedance profile reconstruction algorithm based on time-domain reflectometry (TDR) was developed. Additionally, a novel set of equations to calculate the characteristic impedance and the complex propagation constant from the vector network analyser (VNA) measurements of long lines was found and tested with positive results. Also, a novel single impedance thru-only de-embedding algorithm was completed. Second, the design of a novel rotatable vertical transition. The vertical transition has a 3 dB bandwidth around 35 GHz and small penalties on the eye diagram at 40 Gbit s−1 . Third, positive measured results of these designs in co-fired AlN. The measurements of the co-fired AlN board show similar results than in an LTCC board proving that co-fired AlN is an attractive option for PICs where the thermal management is important. The main conclusion from these findings is that the designed transmission lines and vertical transitions are suitable for the use of LTCC or of co-fired AlN as multi-layer interposers for the packaging of high-speed PICs Future work include improvements to the novel microwave algorithms, the development of equation-based models for the transmission lines. Also, the vertical transition has a resonance around 35 GHz that could be compensated using stubs or other elements. Finally, the transmission line designs and vertical transition designs need to be used for real applications of high-speed PICs using LTCC or co-fired AlN

Superconducting quantum circuits for hybrid architectures

Im Bestreben nach neuen Quantentechnologien gehören supraleitende Quantenschaltkreise (SQS) zu den weltweit führenden Hardware-Plattformen, und finden bereits Anwendung in den Bereichen der Quanteninformationsverarbeitung, Quantenkommunikation und –kryptographie, sowie in der Quantensensorik. Obwohl die Kohärenz solcher Schaltkreise in den vergangenen zwei Jahrzehnten enorm gesteigert werden konnte, existieren konkurrierende Plattformen, die teilweise in bedeutenden Aspekten noch immer überlegen sind. Gerade deshalb erscheint eine Verknüpfung unterschiedlicher Implementierungen zu einer Quantenhybridarchitektur reizvoll, mit dem Ziel, die Stärken der individuellen Plattformen zu kombinieren und gleichzeitig vorhandene Schwächen auszugleichen. In diesem Zusammenhang habe ich im Rahmen meiner Dissertation eine nichtlineare Induktivität für die Verwendung in SQSs entwickelt, die, basierend auf dem ungeordneten Supraleiter „granulares Aluminium“ (grAl), auch in hohen Magnetfeldern verwendet werden kann, was eine Grundvoraussetzung für die Anwendbarkeit in Hybridstrukturen darstellt. Als Machbarkeitsnachweise habe ich den konventionellen Josephson-Kontakt in einem Transmon-Qubit mit dieser grAl-Induktivität ausgetauscht, und die Mikrowelleneigenschaften des Systems im Magnetfeld charakterisiert. Um das Signal-Rausch-Verhältnis der Messung zu verbessern, habe ich zudem einen nicht-entarteten parametrischen Verstärker entwickelt, der auf langen Ketten von Josephson-Kontakten basiert. Die Neuheit des zugrundeliegenden Konzeptes ist dabei die Verwendung von mehreren Eigenmodpaaren der Josephson-Kette, um den Frequenzbereich zwischen 1 und 10 GHz möglichst mit einem einzigen Verstärker abzudecken