Analysis to Measurement
Validation with S-Parameters

Comparison of Interconnect Model Validation with FSV and SPS Metrics

IBIS Virtual Summit with DesignCon 2021, San Jose, CaliforniaIBIS Virtual Summit with DesignCon 2021, San Jose, California

August  2021

Alistair Duffy, De Montfort University
Gang Zhang, Harbin Institute of Technology
Yuriy Shlepnev, Simberian Inc.

Feature Selective Validation (FSV) and S-parameters similarity (SPS) measures  are used in this presentation to evaluate analysis to measurement correlation for Wild River Technology's CMP-28 validation platforms.

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Analysis to Measurement Validation with S-Parameters Similarity Metric

IBIS Virtual Summit at 2021 Virtual 2021 IEEE EMC+SIPI Workshop

August 2021

Yuriy Shlepnev, Simberian Inc.

This presentation introduces evaluation of similarity for two sets of S-parameters with S-parameters similarity (SPS) measure. SPS allows automation of the analysis to measurement validation, comparison of different simulations of the same problem, measurements of the same structure with different tools, as well as finding similar S-parameter models or similar elements within S-matrices. Practical examples are provided.

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Meeting the Demands of PAM4 Systems at 56Gbps and Beyond

July 2019


Alfred P. Neves, CTO, Wild River Technology
Matthew Burns, Product Marketing Manager–High Speed, Samtec

Mike Gianfagna, VP, Marketing, eSilicon

Tim Horel, Director of Field Applications, eSilicon


Abstract
Our discussion will focus on PAM4 (pulse amplitude modulation) systems operating at 56 Gigabits per second and beyond. PAM4 is a modulation technique whereby four distinct pulse amplitudes are used to convey the information. PAM4 enables twice the transmission capacity when compared to binary modulation. Because the additional voltage levels in PAM4 reduce the level spacing by a factor of three, PAM4 is more susceptible to noise than a binary digital signal, thus requiring a higher signal- to-noise (SNR) ratio. Consequently, PAM4 is normally used for short-reach applications where a higher SNR can be obtained.

We will explore how this shortcoming can be overcome, resulting in very long-reach signaling with PAM4 encoding over a copper cable to enable next-generation 25.6 and 51.2Tb/s switches, routers and 800G systems. Delivering this capability has two challenges — working silicon that can deliver the required performance and a SerDes test fixture that allows system designers to verify performance in their target application. We will discuss both challenges. Download white paper.

Watch the related webinar video, High-Performance Communications, Delivered.

A Practical Method to Model Effective Permittivity and Phase Delay Due to Conductor Surface Roughness

DesignCon 2017

Lambert (Bert) Simonovich, Lamsim Enterprises Inc.

Abstract
In the GB/s regime, accurate modeling of conductor loss and phase delay is a precursor to successful high-speed serial link designs. In this paper, a practical method to model effective permittivity and phase delay, due to conductor surface roughness, is presented. By obtaining the dielectric and roughness parameters, solely from manufacturers’ data sheets, phase delay and effective permittivity can now be easily predicted. Detailed case studies and several examples test the model`s accuracy. Download white paper.

BER- and COM-Way of Channel-Compliance Evaluation: What are the Sources of Differences?

DesignCon 2016

Vladimir Dmitriev-Zdorov, Mentor Graphics

Cristian Filip, Mentor Graphics
Chuck Ferry, Mentor Graphics
Alfred P. Neves, Wild River Technology

Abstract
We analyze the computational procedure specified for Channel Operation Margin (COM) and compare it to traditional statistical eye/BER analysis. There are a number of differences between the two approaches, ranging from how they perform channel characterization, to how they consider Tx and Rx noise and apply termination, to the differences between numerical procedures employed to convert given jitter and crosstalk responses into the vertical distribution characterizing eye diagrams and BER. We show that depending on the channel COM may potentially overestimate the effect of crosstalk and, depending on a number of factors, over- or underestimate the effect of transmit jitter, especially when the channel operates at the rate limits. We propose a modification to the COM procedure that eliminates these problems without considerable work increase. Download white paper.

Methods of Improving 3D EM Model Development and Associated Time/Frequency Domain Measurements

DesignCon 2013

Jim Bell and Al Neves, Wild River Technology
Bob Buxton and Jon Martens, Anritsu Company
Josiah Bartlett, Tektronix

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Robust Method for Addressing 12 Gbps Interoperability for High-Loss and Crosstalk-Aggressed Channels

DesignCon 2011

James Bell, Wild River Technology
Alan Blankman
Alfred Neves, Wild River Technology
George Noh
Martin Spadaro

Abstract
This paper addresses a new methodology for 12 Gbps interoperability that combines a concerted family of pathological channels, internal eye monitoring, and external EQ simulation tools, providing insight into an EQ optimization strategy that addresses the specific channel’s mix of crosstalk noise, jitter, and channel loss. This also provides a backplane designer the ability to configure a high-loss, crosstalk aggressed system. The method, combining co-simulation channel optimization, a reconfigurable channel platform, and receiver eye monitoring, has two key benefits; the separation of channel eye opening versus un-equalizable Deterministic Jitter (Dj), and the capability to map loss-crosstalk space for a particular SERDES channel pair, a new concept in SERDES interoperability evaluation. The method is described in detail, followed by relevant case examples using hardware specifically designed for this endeavor. Finally, we compare eye monitor results with the original co-simulation, validating the method.

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Developing Unified Methods of 3D Electromagnetic Extraction, System Level Channel Modeling, and Robust Jitter Decomposition in Crosstalk Stressed 10Gbpsec Serial Data Systems

DesignCon 2011

James Bell
Scott McMorrow
Martin Miller
Alfred Neves

Abstract
As serial link speeds increase, systems become more "Stressed". Loss, low probability deterministic jitter, crosstalk aggression from densely packed signal nets, via and connector impedance and associated resonances, and package and power delivery issues all add their own jitter density function, resulting in a net jitter picture that is inherently complicated. This paper represents a rigorous and practical crosstalk analysis of 10Gbps and higher serial data transmission systems, which will begin at pre-layout 3D EM extraction, continue with the material parameters identification and post-layout analysis and end with direct jitter measurement and separation. We believe this is one of the timeliest of topics in signal integrity at the present time.

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Full-wave time domain modelingFull-wave time domain modelingof interconnects

DesignCon 2010

Martin Schauer
Alfred Neves
Tom Dagostino
Scott McMorrow

Abstract
Frequency-domain 3D Electromagnetic modeling approaches always have the potentialFrequency-domain 3D Electromagnetic modeling approaches always have the potentialfor causality and passivity violation issues, especially when applied to greater than20Gbsec data rates applications: initial applications for 3D Electromagnetic modelingmethods were only used in low bandwidth frequency-domain microwave designs.A new and inherently passive and causal time-domain oriented approach for 3DElectromagnetic modeling is introduced in detail. The authors show specific advantagesof this approach for baseband-NRZ very high-speed backplanes, interconnects, andgeneral board design for digital systems. Selecting the correct loss model will be includedand the model results will be compared to actual measurements to 20 GHz using a testboard specifically designed for this presentation.

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Practical identification of dispersive dielectric models with generalized modal S-parameters for analysis of interconnects in 6-100 Gb/s applications

DesignCon 2010

Yuriy Shlepnev, Simberian Inc.
Alfred Neves, Teraspeed Consulting Group
Tom Dagostino, Teraspeed Consulting Group
Scott McMorrow, Teraspeed Consulting Group

Abstract
A novel method for extraction of dispersive dielectric parameters to 50 GHz is proposed. The method doesn’t require advanced de-embedding, and is based on correlation of measured and simulated generalized modal S-parameters of a line segment. First, VNA measurements for two line segments are made and used to compute generalized S-parameters of a difference segment. Second, 3D full-wave model of the difference segment with conductor model with roughness is used to identify the dielectric properties. We finalize the paper with the derivation of dielectric models for low-cost FR4-type and for expensive low-loss high-frequency materials. The advanced models can be used for practical electromagnetic analysis of interconnects for the 6-100 Gb/s realm.

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Measurement-Assisted Electromagnetic Extraction of Interconnect Parameters on Low-Cost FR-4 Boards for 6-20 Gb/sec Applications

DesignCon 2009

Y. Shlepnev
A. Neves
T. Dagostino
S. McMorrow

Abstract
Design of interconnects on PCBs for 6-10 Gb/s data rates requires electromagnetic models from DC up to 20 GHz. Manufacturers of low-cost FR-4 PCBs typically provide values for dielectric constant and loss tangent either at one frequency or without specifying frequency value at all, that is not acceptable for the broad-band models. A simple and practical methodology to extract frequency-dependent dielectric parameters on the base of correlation of measurements and simulations is proposed. A board with 30 test structures has been built to validate the extraction methodology and to verify possibilities to predict interconnect parameters with the electromagnetic analysis.

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alibration and De-Embedding Techniques in the Frequency Domain

DesignCon 2009

Tom Dagostino
Alfred Neves

Abstract

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