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Framingham Center, MA, United States

Johns D.P.,CST of America Inc.
Symposium Digest - 20th URSI International Symposium on Electromagnetic Theory, EMTS 2010 | Year: 2010

TLM is a well established full wave time-domain method for solving electromagnetic fields. TLM has been successfully applied to a diverse range of problems, including microwave component and antenna design, and it is particularly well-suited to EMI analysis. This paper reviews the developments of TLM for EMC/EMI analysis and presents a simulated aircraft lightning application. © 2010 IEEE. Source


Scogna A.C.,CST of America Inc. | Wu T.-L.,National Taiwan University | Orlandi A.,University of LAquila
IEEE Transactions on Advanced Packaging | Year: 2010

A photonic crystal fence is proposed for simultaneous switching noise mitigation in power/ground plane pairs with minimum use of the high dielectric constant for the rods. In particular a 45 degree rotated square lattice consisting in three rows of periodic rows is used for the fence. Broadband and high efficient noise suppression can be still achieved while minimizing the cost of the structure. A sensitivity analysis investigating the impact of 1) the normalized rods radius, 2) the number of rods rows, and 3) the value of the dielectric rods is performed and design parameters for the calculation of the stop bands are extracted. The normalized radius is not sufficient to correctly predict the stop band of the fence; instead multiple design parameters are necessary. It is found that an extra row of high dielectric constant material introduces an attenuation for the noise coefficient of around 8-10 dB per row and multiple stop bands are predicted while increasing the relative dielectric constant of the rods from 50 to 300. A one-dimensional circuit model is finally developed for a quick and efficient prediction of the stop band performances of these structures. © 2006 IEEE. Source


Johns D.,CST of America Inc.
IEEE Electromagnetic Compatibility Magazine | Year: 2016

This article will explore the use of electromagnetic simulation when hardening facilities against EMP and lightning. EMP is a high-intensity burst of electromagnetic energy that can potentially cause major disruption to vital infrastructure such as telecommunications, electrical power, banking and finance, emergency services, medical facilities, transportation, food and water supply. Lightning can cause significant damage by directly striking a building, when metallic structures such as electrical wiring provide return current flow in an attempt to equalize potentials. It is therefore essential to protect or "harden" critical facilities by stringent electromagnetic design, including shielding to block incident EMP fields, careful treatment of points of entry (POE) and diversion of lightning currents using down-conductors. This article shows how a simulation of the performance of EMP protection measures at the point of entry, such as filtering and clamping, can be set up and carried out. The simulation of a lightning strike to a building structure is also demonstrated, to show how the induced current return paths can be visualized in order to characterize the possible effect of the lightning strike on systems inside the building. This includes an investigation of cable system positioning inside the building and the prediction of induced shield and internal load currents and the analysis of lightning protection system (LPS), taking into account the effect of down-conductor type and grounding impedance. © 2012 IEEE. Source


Scogna A.C.,CST of America Inc. | Zhang J.,Cisco Systems
Microwave Journal | Year: 2012

As digital circuits became faster, direct coupling among power planes in multilayer printed circuit boards (PCB) became a major concern for signal integrity/power integrity and electromagnetic interference (EMI). Fast signals produce electromagnetic waves that can propagate by means of the parallel plates in the PCB, induce noise on the signals passing through the power bus (vias) and radiate from the edge of the board. The present study focuses on the analysis of the noise that propagates from a power plane to another power plane due to their proximity. To mitigate this problem, proper design of both power and ground planes in the stack-up is illustrated. A test board is fabricated and measurements are performed in order to validate the numerical electromagnetic model. Source


Lai M.,Intel Corporation | Kostka D.,CST of America Inc. | Casanova J.,Intel Corporation | Seshadhri M.,Intel Corporation
IEEE International Symposium on Electromagnetic Compatibility | Year: 2013

Passive channels pose significant challenges to the serial link transmission for single-ended buses running at very high speed. This paper will cover different aspects of the challenges in modeling chips, packages, PCB's, connectors and their interactions. The goal of the paper is to show full 3D link as well as hybrid 2D/3D link correlation for both passive (TDR/VNA) and active (system margins) measurements for a high speed memory bus. Full wave electromagnetic (EM) modeling is utilized to take into account important phenomena such as surface roughness and dispersive material behavior. The impact on system-level performance is analyzed by comparing results with and without crosstalk from adjacent lanes. © 2013 IEEE. Source

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