Selected past presentations and available recorded conference talks are posted here for viewing or download.
How Can Design Engineers Solve EMI/EMC at the PCB Design Phase?
Presented for Denpaflux (Formerly Mitai) (Feb 28, 2024)
PCB design is a key area where EMI problems frequently arise, often due to issues with component placement, routing, and grounding within the layout. To address these challenges, design engineers must identify potential EMI problems early on and take proactive steps to resolve them before reaching EMC compliance testing. In this recorded webinar, led by PCB design expert Zachariah, you will gain valuable insights into how stackup and routing influence EMI, along with effective grounding strategies to prevent common EMI issues. You'll also get a sneak peek into a new EMC solution tool that significantly reduces manual hours spent on EMI troubleshooting. This recording is ideal for design engineers looking to enhance their skills and stay up-to-date with the latest EMC tools, as well as individuals aiming to improve their expertise in the competitive electronics industry. If you're curious about how a new tool can solve EMC issues at the design level, this webinar is for you.
PCB Design and Simulation Challenges in 224G Interconnects
Presented at EDI CON Online 2023 (Oct 4, 2023)
The fastest data rates being implemented in data center architecture is 224G PAM-4, which supports a variety of interconnect types between servers, routers, and other infrastructure. At the board and chip level, the PCB and package exhibit certain design challenges that can degrade signal integrity in 224G PAM-4 channels. To overcome these challenges, greater collaboration between PCB design applications and simulation applications is needed. In this presentation, we outline some of the design challenges present in boards and packages supporting 224G PAM-4 channels. We will explore signal integrity issues (crosstalk, losses, resonances) in boards and packages interfacing with 224G PAM-4 channels in simulation, and we qualify certain design guidelines using a new integrated design and simulation solution linking Altium and Ansys. Attendees will have a chance to see the typical design approaches that are being proposed and implemented in 224G PAM-4 channels.
Differential Pair Design for 112 Gbps and Faster Systems
Presented at EOT 2023, Herning, DK (May 11, 2023)
Differential serial channels are pushing towards 56 GHz Nyquist to target 112G NRZ and 224G PAM-4 per lane. Differential interconnects targeting these bandwidths will be implemented in package substrates and in PCBs, although the fundamental design concepts present in both domains are essentially the same. While the core concepts apply in both domains, the challenges involved in package and PCB design are quite different. In PCBs, differential pairs designed to target these bandwidths must content with many challenges relating to via design, material selection, and differential crosstalk into slower channels. This presentation outlines these design challenges and how the fundamental approaches to differential pair design extend to 56 GHz bandwidths. Simulation examples from Simbeor and design examples from Altium Designer are presented to illustrate design implementation and approaches to working at 56 GHz.
Interconnect Design for Advanced Phased Array Systems
Presented at EDI CON Online 2022 (Oct 19, 2022)
Many systems are integrating capabilities that require mmWave beamforming. Example application areas include suites of sensors, 5G/6G systems, radar, and SATCOM. In this presentation, a review of best design practices surrounding interconnect design required to route signals into phased array structures required in these application areas will be presented. The core of this presentation will examine the process and theory required to design transmission lines and antenna arrays for these systems. In addition to transmission lines for these systems, the placement and arrangement of antennas in the array, as well as oscillator and transceiver elements, will determine the beamforming capabilities of these systems. Examples from industry and research literature will be presented to illustrate practical usage of these concepts and the diversity of systems to which they apply.
Where High Speed Meets High Frequency
Presented at AltiumLive 2022 CONNECT (Jan 28, 2022)
As many design teams may have experienced, high speed designs are confronted with many of the signaling and layout challenges seen in high frequency designs. High speed interconnect design should take a similar approach seen in high frequency design with respect to losses, impedance determination, and analysis. In this technical session, I’ll explore some of the correspondences between high speed PCB design and analysis as they relate to the fundamental concepts in high frequency design. Topics like interconnect design, measurement, and analysis will be examined while comparing the design approaches in high speed and high frequency PCB layout and routing. The goal is to help high speed design teams become more familiar with the conceptual explanations for why very high speed signal integrity problems occur and how they can be overcome with some smart design and layout decisions.
PCB Design Optimization: What it Means and New Methods
Presented at PCB West 2021 (Oct 6, 2021)
PCB designers often speak of “design optimization,” and causal PCB design optimization has found a stronger mathematical footing in the engineering literature over the last 10 years. In particular, transmission line design requires satisfying multiple design objectives and constraints that may be in conflict, and engineers need tools and methods to help them balance design objectives while staying within their design constraints. For ultra-high-speed boards, designers need to optimize transmission line designs within the relevant signal bandwidth, which can extend to hundreds of GHz. This presentation outlines the current state of PCB design optimization techniques used to produce useful designs, while balancing multiple design goals. An alternative method for design optimization from analytical equations describing transmission lines will be presented. The presented method is applicable to any transmission line with a known analytical or numerical model, and the method uses standard evolutionary computation techniques to optimize the design. Similar techniques can be implemented in advanced field-solver tools, but designers with basic coding skills can use some simple open-source packages to build their own design optimization routines for transmission lines.
Building and Using Numerical and Analytical Models in PCB Interconnect Optimization
Presented at EDICON 2021 (Aug 11, 2021)
PCB optimization focuses on designing boards to meet specific performance metrics while satisfying specific design constraints. In particular, interconnect design requires satisfying multiple design objectives and constraints that may be in conflict, and engineers need tools and methods to help them balance design these objectives while staying within their design constraints. For ultra-high-speed boards, designers need to optimize transmission line designs within the relevant signal bandwidth, which can extend to hundreds of GHz. Newer signaling specifications and standards (e.g., USB4, DDR5, and IEEE 802.3 standards) require this type of optimization. In this presentation, the use of model extraction, design exploration, and fusion of analytical/numerical models will be presented with the goal of developing models for broadband design optimization. For PCB transmission lines, a model that accounts for copper roughness and dispersion with numerical or analytical impedance models will be presented. These concepts fit within recent research on novel CAD and field solver methodologies to address high speed/high frequency interconnect design challenges.
Random Laser Dynamics in Disordered and Semi-ordered Cavities
Presented at IEEE RAPID 2021 (Aug 4, 2021)
Random lasers are unique systems where lasing occurs via repetitive scattering in a disordered nanostructure with gain. Theoretical descriptions that can provide a framework for understanding temporal instabilities leading to high-intensity emission is lacking in the literature and requires a time-dependent theory that accounts for stability conditions. Herein, instability conditions for multimodal lasing will be derived from self-consistent time-dependent laser theory. An equation of motion describing relaxation oscillations in a CW random laser in the single-mode and multimode cases will be presented. Stability and equations of motion describing multimodal stability will be presented. Conditions leading to unstable behavior, as well as spatially-confined mixed instabilities and relaxation oscillations in multimode random lasing with spatial overlap will be discussed. These results apply to semi-ordered and totally random semiconducting lasers and can be generalized to other materials.
Advances and Challenges in Automotive Radar Module Design
Presented at EMC Live 2021: Automotive (Jun 6, 2021)
Radar modules used in new automobiles have seen many advances at the chip level, board level, and signal processing level. Newer modules face multiple challenges related to increasing point cloud density, prevent on-module and inter-module interference, and coexistence with other wireless protocols, particularly as 5G rollouts get pushed into higher frequencies. This presentation will review recent advances in automotive radar design with an eye towards EMI suppression, as well as advances in other design aspects that have helped increase accuracy in these systems. Finally, some newer design paradigms will be presented with an eye towards EMI suppression in car radar modules.
Causal Transmission Line Geometry Optimization for Impedance Control in PCBs
Presented at IEEE EPEPS 2020 (Oct 7, 2020)
In printed circuit boards (PCBs) and integrated circuits (ICs), transmission lines are designed to route digital or analog signals between driver and receiver components. Any transmission line should be designed to minimize signal distortion and ringing, although achieving multiple design goals is not always feasible. Prior discussions of transmission line optimization have focused on linking experimentally observed signal behavior to empirical circuit models (e.g., RLGC(f) model) with Lorentzian or wideband Debye dispersion. The link between transmission line geometry and causal digital signal behavior, and a procedure for optimizing transmission line geometry, will be presented and discussed. The procedure shown here can be used with other transmission line geometries and analog signals with well-defined bandwidth. Signal distortion metrics and S-parameters could also be incorporated as additional objective functions.
Unstable Emission From Random Lasers
Presented at IEEE Photonics Society SUM 2019 (Jul 8, 2019)
Random lasers are unique systems where scattering contributes to formation of high-Q resonances in a random structure. The theoretical descriptions of these systems has largely been statistical or phenomenological until only recently, calling into question the origins and mechanisms governing formation of strong instabilities in these systems. In this presentation, the conditions leading to instability are derived from the author’s development of a time-dependent, self-consistent random laser theory. Stability conditions are derived directly in this system under the consideration of relatively long pulses compared to the carrier relaxation time. These results indicate the potential for relaxation oscillations with unique spatial structure and a Hopf bifurcation during excitation. Instabilities are analyzed as Poincare’-Bendixson phenomena to derive some conditions leading to stable or unstable transient behavior.
Zinc Oxide Random Lasers: Controlling the Emission Properties
Presented to Tektronix Advanced Metrology Group (Oct 25, 2017)
Random lasers are unique optical systems where high-Q laser modes are formed via resonant scattering in a gain medium, leading to a variety of lasing phenomena that are facilitated by the random structure of these systems. In this presentation, experimental and theoretical results are presented to illustrate how systems designers can exert some control over the emission characteristics of random lasers. Such methods for control include pulse shaping, embedded high-Q structures in random gain media, and addition of lossless scatterers to maximize net gain in the system.
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