2007 ieee international symposium on electromagnetic compatibility

24EMC <strong>2007</strong> ADVANCE PROGRAMwith feedback technique is also evaluated with the board level filternetwork.SHIELDINGShielding Specification Techniques and MeasurementMethods for AircraftWilliam Prather, U. S. Air Force Research LaboratoryIf properly implemented, electromagnetic shielding can protect aircraftelectronics from harmful interference over a wide range of frequencies.The first step is to create a properly written set of specificationsin measurable engineering units. If this is done, then theshielding system can be analyzed and measured in the laboratory andon board the aircraft. Using large aircraft as an example, this paperdiscusses shielding element specifications and the measurementmethods that can be used to verify them. Illustrative examples ofmeasured data are presented.Shielding Effectiveness of a Wire MeshHans A. Wolfsperger, Emscreen GmbHThis paper describes an analytic solution to determine the shieldingeffectiveness (SE) of an infinite wire mesh. The electromagnetic couplingthrough the holes is represented by electric and magneticdipoles, according to Bethe’s theory. The dipoles are interacting witheach other. They are rearranged in a way that allows calculating thereactive field strength as an infinite sum. Finally, the SE is calculatedunder consideration of the mesh’s conductivity.Evaluation of the Electromagnetic Penetration of the NASASpace Shuttle Endeavour Using an Ultra-WidebandMeasurement SystemRobert Johnk, National Institute of Standards and Technology (NIST);Robert Scully, NASA; David Novotny, NIST; Chriss Grosvenor, NIST; NinoCanales, NIST Emeritus; Dennis Camell, NIST; and Galen Koepke, NISTThis paper summarizes a joint NIST-NASA measurement effort toevaluate the electromagnetic penetration of the shuttle Endeavour.NASA is concerned about the effects that microwave imaging radarsystems might have on critical avionics systems on its fleet of spaceshuttles. As part of a multifaceted effort, a portable, NIST-developed,ultra-wideband measurement system was deployed at theKennedy Space Center to evaluate electromagnetic penetration overthe frequency range of 30 MHz to 6 GHz at selected locations insideEndeavour. The measurements were carried out inside a large metalhangar, which exhibited robust reverberant behavior. A combinationof reverb chamber techniques and time/frequency signal processingpermitted the evaluation of electromagnetic penetration at six differentlocations inside the orbiter.Engineering of Absorbing Gaskets Between Metal PlatesMarina Koledintseva; Sandeep Chandra; and James Drewniak, —University of Missouri-Rolla; and James Lenn, General Dynamics LandSystemsEngineering of absorbing material for gaskets that would be usedbetween two metal plates to reduce electromagnetic emissions andimprove immunity of electronic equipment is considered. An analyticalmodel of a composite based on the Maxwell Garnett formulationfor multiphase mixtures, as well as the shielding effectiveness ofthis material, are presented. The full-wave numerical computationalresults for the structure consisting of two overlapping metal platesand an engineered gasket composite material in the place of the overlapare presented.Protective Properties of a Generic Missile Enclosure toDifferent Electromagnetic InfluencesSven Fisahn, University of Hannover; Heyno Garbe, University ofHannover; and Frank Sabath, WISElectronic components and subsystems of a time critical system (e.g.an aircraft) must be highly unsusceptible to electromagnetic influences.In order to predict the immunity of a generic missile(GENEC) against electromagnetic influences, not only the electronicsystem but also the enclosure has to be taken into consideration.Assuming a sufficient conductivity of the metallic enclosure, aperturesin this enclosure effect a substantial reduction of the shieldingeffectiveness. The shielding properties of the generic missile could beinvestigated by means of a metallic hollow cylinder equipped withdifferent apertures. Numerical simulations and measurements of thiscylinder will be carried out and analyzed.Rethinking Shielding TheoryDavid Larrabee, East Stoudsburg UniversityThe traditional “shielding theory” for the shielding effectiveness ofenclosures is examined. It is shown that there can be significanteffects which are not included within a simple barrier based theory athigh frequencies. It is shown that a 1-dimensional box (using the fullMaxwell’s equations solution) has 1-D resonances that can significantlyaffect the accuracy of a barrier based shielding calculation.Treating the enclosure as a resonant cavity with perturbations on thewalls is a better approach to the analysis of radiated emissions andradiated susceptibility problems at high frequencies (at and above thefirst resonance). This has the added advantage of having been workedout quite thoroughly for wave guides and resonant cavities.CABLES AND TRANSMISSION LINESOn Eliminating Crosstalk in a MulticonductorTelecommunication CableRoblot Sandrine; and Zeddam Ahmed, — France Telecom R&DThis paper presents a method of crosstalk reduction in a telecommunicationcable composed of multiple conductors. Initially, an electromagneticand topologic code is implemented to simulate themulti conductor transmission line when injecting the different signalsfollowing a particular combination of modes. Then, the far endcrosstalk voltage is determined. To picture those results, thecrosstalk results obtained by simulation will finally be injected on areal line transmitting VDSL signal. With such a method, it appearsthat is possible to decrease crosstalk on the line, and consequently toincrease the bit rate level and reach of xDSL transmissions. Somestudies have already been undertaken to minimize crosstalk. Theseapproaches have been experimented on printed circuits, microstrip,etc. but rarely on telecommunication cables, which require a differentialmode transmission of signals and use a frequency band thatextends from 12 kHz to 30 MHz.A Study on Suppression of Crosstalk Between ParallelTransmission Lines in the High Frequency BandTakashi Kasuga, Nagano National College of Technology; and HiroshiInoue, Akita UniversityAs the parallel transmission line is used in the high frequency range,it is necessary to decrease the crosstalk S41 between transmissionlines (TLs). This study shows the basic idea of some effective structureswhich can suppress the S41. When the distance between TLsis significantly varied, the S41 is also varied at the resonance frequency.As the crosstalk S41 are measured and calculated for four©<strong>2007</strong> IEEE www.emc<strong>2007</strong>.org