2007 ieee international symposium on electromagnetic compatibility

EMC <strong>2007</strong> ADVANCE PROGRAM 17imbalance on radiated emission of cables inside a commercial 19-inchrack-based cabinet. Scattering parameters (S-parameters) for two setsof cable assembly are measured with a four-port vector network analyzer(VNA) and converted into mixed mode S-parameters. Timedomaininput signals with different slew rates and different amountof skew are transferred into frequency-domain using fast Fouriertransform (FFT). The spectra of radiation emission associated withdifferent inputs are then estimated.EMI Emissions from Mismatches in High Speed DifferentialSignal Traces and CablesBruce Archambeault; Jay Diepenbrock; and Sam Connor, — IBMCorporationThe use of so-called differential signaling for high speed signals hasbecome very common in today’s high speed system designs. While thissignal strategy allows better data quality and signal integrity, there aresome significant EMC and signal integrity issues that are not readilyapparent. This paper demonstrates that a significant amount of common-modecurrent can be created when the two legs of the differentialsignal are skewed in time, or if the rise and fall times of the signals differ.These common mode currents can impact the EMC performance,causing significant levels of emissions unless careful design considerationis given to shielding and common-mode (ground) current return.EMI Design of Shielded Cable AssembliesJim Nadolny, SamtecMost discussions on shielding for EMC address the shielding of enclosuresand give rules of thumb regarding the size of slots and holes.These recommendations are not applicable in general to the design ofshielded cable assemblies. Because there exists a gap in publishedinformation on the unique shielding requirements for cable assemblies,this document was generated. The scope of this document isthat it will apply to low cost, shielded multiconductor, cable assemblies.While some of this information will be applicable to coaxial RFcable assemblies, this is not the main focus of this document.EMC MEASUREMENTS IIAnalysis of Radiated Emissions and Shielding Effectivenessfor a Metallic Enclosure with Shielding SpringsGiulio Antonini, University of L’Aquila; Antonio Orlandi, University ofL’Aquila; and Antonio Ciccomancini, CST of AmericaThe high speed digital processing in modern electronic products hasmade more difficult the achievement of conformity about limits emissions.To verify the requirements of standards on these emissions theuse of a metallic enclosure is often necessary; in this way the powerradiated by the system is reduced. In this paper the radiated emissionsand the shielding performance of a metallic rack with shielding springsare studied both by dedicated experiments and by simulations. Aninternal source represented by a loaded monopole antenna is used toinvestigate the radiated emissions 3 meters from the box. A simplifiedmodel of the antenna source is proposed in the numerical model and agood agreement over a frequency range up to 1 GHz is achievedbetween measured results and simulated results. Shielding effectivenessis finally evaluated by means of two different kinds of sources: 1)near field (internal source) and 2) far field (plane wave source).Logistic Regression in Immunity TestingGiorgio Giunta; and Bruno Audone, — Oerlikon ContravesLogistic Regression, a statistical analysis tool used for epidemiologicalstudies, can be successfully exploited to interpret susceptibilitytest results with the twofold aim of understanding which are themost significant causes affecting the Device under Test (DUT) and ofproviding a technique to define a global figure of safety margin whenmany test parameters are involved. The background of LogisticRegression is briefly summarized and then a graphical interpretationof test results is provided. Finally, the experimental validation of themethod is described.The Proposal of a New Approach to Immunity TestingMichela Audone, Centro Ricerche Fiat; and Bruno Audone, OerlikonContravesThe need of performing immunity tests with the aim of meeting therequirements of Functional Safety is addressed proposing severalapproaches based upon the data processing of test results. This representsa clear improvement with respect to the present situation ofEMC standards based upon simple qualitative checks, which do notoffer any warranty of safety. Even if the equipment under test (EUT)is declared immune in normal operative conditions, it may happenthat a simple environmental effect such as temperature variation hascatastrophic consequences. The test results of radiated immunitytests performed on a DC/DC converter are processed according to theAnova model, which is one of the proposed approaches.REVERBERATION CHAMBER MEASUREMENTS IReverberation Chamber Calibration: Differences in ResultsWhen Using a Slot Instead of a Dipole AntennaTobias Aurand; John Dawson; Andrew Marvin; and Martin Robinson, —University of YorkThis paper considers the use of a slot antenna in the calibration of areverberation chamber. In using a slot antenna the need for a balunis reduced which simplifies antenna construction. The behaviour ofa slot antenna is compared to a dipole antenna and it is found that thefield uniformity results obtained with a slot are more pessimisticthan the ones with a dipole. Whilst the slot is usable for calibrationof a reverberation chamber, it seems that the slot is more sensitive tosome field nonuniformities than the dipole.Pulsed Power 3 GHz Feasibility Study for a 36.7 m3 ModeStirred Reverberation ChamberOlof Lunden, FOI; and Mats Bäckström, Saab CommunicationA feasibility study was conducted to investigate the field build upprocess in a 36.7 m3 reverberation chamber. The time to get a steadyfield state in the unloaded chamber will normally be about 10 to 20µs. However, it is of great interest to investigate what field levels canbe expected for an ordinary radar source. The particular 700 kW S-band radar we have at our disposal has a typical pulse duration of 1µs. A maximum field strength of approximately 35 kV/m wasachieved for 309 kW of input power. The voltage ratio, VR, betweenthe ensemble maxima, with a chamber time constant equal to about10 µs and the magnetron pulse of only 1 µs, was found to be 0.54 or-5.4 dB. The pulse characteristics have also been investigated whenloading the chamber according to the aviation test standard RTCADO-160.Enhanced Backscatter in a Reverberation Chamber: Inside EveryComplex Problem is a Simple Solution Struggling to Get OutJohn Ladbury; and David Hill, — National Institute of Standards andTechnology (NIST)We encountered problems when we attempted to model the behaviorof a transmitting antenna in a reverberation chamber. Our model©<strong>2007</strong> IEEE www.emc<strong>2007</strong>.org