Showing papers on "Electromagnetic compatibility published in 2002"

Low stray inductance bus bar design and construction for good EMC performance in power electronic circuits

Abstract: Ten years after the publication of the EC Directive 89/336 on electromagnetic compatibility, the impact of this directive on design and lay-out of modern electrical and electronic equipment can be observed. Many research and development studies have proposed and evaluated detailed improvements in the area of component design, component selection, circuit lay-out, shielding and active and passive filtering. New and innovative solutions to minimize noise, especially common mode conducted electromagnetic interference (EMI), in power electronic circuits continue to be developed. In this paper, the authors investigate to what extent EMI caused by power electronic devices in hard switching inverter topologies can be minimized using ultra-low inductive planar busbars. The concept followed in this study is to tackle EMI directly at the source where most EMI is generated; in other words, to reduce the parasitic magnetic energy stored in the inverter DC link to reduce high voltage spikes during switching. A planar busbar was built, tested and analyzed. Measurements show the validity of the theoretical, but simple, design procedure for planar busbars in power converters.

Interference in implanted cardiac devices, Part I.

Abstract: Sensing intrinsic cardiac electrical activity is essential for the function of pacemakers and implantable cardioverter defibrillators (ICDs). Examples of undesired triggering or inhibition of pacemaker output by extraneous signals were identified early after the introduction of noncompetitive, “ demand” pacemakers. Hermetic shielding in metal cases, filtering, and interference rejection circuits, together with a preference (much more marked in the United States 1 than in Europe 2 ) for bipolar sensing, made contemporary pacemakers and ICDs relatively immune to electromagnetic energy sources in homes and workplaces. Sources of electromagnetic interference (EMI) remained ubiquitous in the medical environment. However, they were predictable and avoidable. New technologies that use more of the electromagnetic spectrum (i.e., wireless telephones, electronic article surveillance [EAS] devices) have rekindled interest in EMI risks for patients with implanted cardiac devices. Although these technologies do not constitute a major public health threat, adverse interactions can occur. The counterpart to EMI is electromagnetic compatibility, a science aimed at avoiding interference potential by adding shielding or redesigning circuits against specific EMI sources. There are three essential elements to any electromagnetic compatibility problem. There must be an electromagnetic source, a receptor or victim (in our case the implanted cardiac device) that cannot function properly due to the electromagnetic phenomenon, and a path between them that allows the source to interfere with the receptor. Each of these three elements must be present, although they may not be readily identified in every situation. Identifying at least two of these elements and eliminating (or attenuating) one of them generally solves electromagnetic compatibility problems. Collaboration among industry, physicians, regulatory agencies, and consumer groups will hopefully achieve full compatibility between implanted devices and other technologies. This will require adoption of international standards establishing the upper limit of permissible field intensities for the whole electromagnetic spectrum. Implanted devices should not react to fields below this limit; more intense fields will be prohibited. This two-part review discusses EMI with implanted cardiac devices. The first part of the review addresses general concepts and specific sources of EMI in everyday life and the workplace. The second part focuses on medical sources of EMI, highlighting preventive measures.

Handbook of Electromagnetic Compatibility

Abstract: Fundamentals and Physics of Electromagnetic Interference: Units, Symbols, Theorems, Definitions, and Basic Formulas, Electromagnetic Theory and Fundamentals of EMC, The Physics of Interference Phenomena. Analysis and Prediction for EMS: Plane Wave Coupling to Cables, Crosstalk, Conducted and Radiated Emissions, Computer Methods for EMC Analyses and Prediction. Methods to Ensure EMC: Grounding and Bonding, Electromagnetic Shielding, Conduction Filters. Commercial and Military Standards and Methods: International Radio Frequency Emission Control Requirements for Commercial Equipment, International Electromagnetic Immunity Requirements for Commercial Equipment, Military EMC Standard and Methods, MIL-STD-461 and MIL-STD-462, Other MIL-Based Standards. EMC Measurements: Methodology for Electromagnetic Interference Measurements, Standard Antennas for Electromagnetic Compatibility Measurements, EMC Compliance Test Facilities, Alternate EMC Compliance Test Facilities. Radio Systems, Sparks and Pulses, Biological Effects, Fibre Optics, and Plasmas: Principles of Radio Systems and Relevant EMI Environmental Effects, Analysis and Computation, Radio Systems Parameters Performance Criteria Concerning Computation and Mitigation of EMI Effects, Electrostatic Discharge, Lightning, The Nuclear Electromagnetic Pulse, Biological Effects of Electromagnetic Fields, Fibre Optics for EMC, Plasma Effects in EMC.

A simulation model for electromagnetic transients in lightning protection systems

Abstract: This paper deals with the evaluation of electromagnetic transients in a lightning protection system (LPS). A field approach is used, based on the numerical solution of a modified version of the thin-wire electric field integral equation in the frequency domain. Time profiles of interesting electromagnetic quantities are computed by using a discrete fast Fourier transform algorithm. The model takes into account coupling effects among aerial parts and ground electrodes in order to correctly estimate the quantities which can determine electromagnetic hazard inside the LPS; transient touch and step voltages can be easily evaluated also taking into account the human body presence on the soil surface. To this purpose, a crucial point is the accurate evaluation of the current distribution among the earthed branches of the LPS and this needs to correctly consider mutual electromagnetic interference among the aerial parts and the earth-termination system of the same LPS. A suitable approach to consider the lossy soil is employed. Validation of the proposed model is performed by comparing the results with those measured and computed available in technical literature. Simulation examples related to realistic LPS structures are presented and discussed to show the flexibility and the accuracy of the model in the range of practical applications inside the volume to be protected.

Susceptibility analysis of wiring in a complex system combining a 3-D solver and a transmission-line network simulation

Abstract: This paper deals with the application of electromagnetic field-to-transmission-line coupling models for large cable systems analysis. It emphasizes the use of Agrawal's (1980) model applied here in a numerical simulation of an electromagnetic susceptibility problem up to 500 MHz. Based on the concepts of EM topology, the proposed methodology consists in calculating the incident fields with a three-dimensional (3-D) computer code and the coupling on cables with a multiconductor transmission-line network computer code. In order to validate the efficiency of this methodology in an industrial context, an experiment has been performed on a prototype wiring installed in a Renault Laguna car, stressed by an EM plane wave. Numerous validation configurations have been carried out. First, the prototype cable network under study has been tested on a ground plane to validate the coupling model but also, to validate the cable-network topology itself. Second, EM fields have been measured onto the structure and inside the structure. Then, they have been compared to 3-D calculations, performed with an FDTD code. Third, comparisons between measurements and calculations of bulk currents and voltages on 50 /spl Omega/ loads on the wiring have been achieved.

Electromagnetic Anechoic Chambers: A Fundamental Design and Specification Guide

Abstract: Foreword. Preface. 1 Introduction. 1.1 The Text Organization. References. 2 Measurement Principles Pertaining to Anechoic Chamber Design. 2.1 Introduction. 2.2 Measurement of Electromagnetic Fields. 2.2.1 Introduction. 2.2.2 Antennas. 2.2.3 Radiated Emissions. 2.2.4 Radiated Susceptibility. 2.2.5 Military Electromagnetic Compatibility. 2.2.6 Antenna System Isolation. 2.2.7 Radar Cross Section. 2.3 Free-Space Test Requirements. 2.3.1 Introduction. 2.3.2 Phase. 2.3.3 Amplitude. 2.3.4 Polarization. 2.3.5 The Friis Transmission Formula. 2.4 Supporting Measurement Concepts. 2.4.1 Introduction. 2.4.2 Coordinate Systems and Device Positioners. 2.4.3 Decibels. 2.4.4 Effects of Reflected Energy. 2.4.5 Effects of Antenna Coupling. 2.5 Outdoor Measurement Facilities. 2.5.1 Introduction. 2.5.2 Electromagnetic Design Considerations and Criteria. 2.5.3 Elevated Outdoor Antenna Range. 2.5.4 Ground Reflection Antenna Range. 2.5.5 Open-Area Test Sites (OATS). References. 3 Electromagnetic Absorbing Materials. 3.1 Introduction. 3.2 Microwave Absorbing Materials. 3.2.1 Pyramidal Absorber. 3.2.2 Wedge Absorber. 3.2.3 Convoluted Microwave Absorber. 3.2.4 Multilayer Dielectric Absorber. 3.2.5 Hybrid Dielectric Absorber. 3.2.6 Walkway Absorber. 3.3 Low-Frequency Absorbing Material. 3.3.1 Introduction. 3.3.2 Ferrite Absorbers. 3.3.3 Hybrid Absorbers. 3.4 Absorber Modeling. 3.5 Absorber Testing. References. 4 The Chamber Enclosure. 4.1 Introduction. 4.2 Electromagnetic Interference. 4.3 Controlling the Environment. 4.4 Electromagnetic Shielding. 4.4.1 Introduction. 4.4.2 The Welded Shield. 4.4.3 The Clamped Seam or Prefabricated Shield. 4.4.4 The Single-Shield Systems. 4.5 Penetrations. 4.6 Performance Verification. 4.7 Shielded Enclosure Grounding. 4.8 Fire Protection. References. 5 Anechoic Chamber Design Techniques. 5.1 Introduction. 5.2 Practical Design Procedures. 5.2.1 Introduction. 5.2.2 Quick Estimate of Chamber Performance. 5.2.3 Detailed Ray-Tracing Design Procedure. 5.3 Computer Modeling. 5.3.1 Introduction. 5.3.2 Ray Tracing. 5.3.3 Finite-Difference Time-Domain Model. 5.4 Other Techniques. 5.5 Antennas Used In Anechoic Chambers. 5.5.1 Introduction. 5.5.2 Rectangular Chamber Antennas. 5.5.3 Antennas for Tapered Chambers. 5.5.4 EMI Chambers. References. 6 The Rectangular Chamber. 6.1 Introduction. 6.2 Antenna Testing. 6.2.1 Introduction. 6.2.2 Design Considerations. 6.2.3 Design Example. 6.2.4 Acceptance Test Procedures. 6.3 Radar Cross-Section Testing. 6.3.1 Design Considerations. 6.3.2 Design Example. 6.3.3 Acceptance Test Procedures. 6.4 Near-Field Testing. 6.4.1 Introduction. 6.4.2 Chamber Design Considerations. 6.4.3 Design Example. 6.4.4 Acceptance Test Procedure. 6.5 Electromagnetic Compatibility Testing. 6.5.1 Introduction. 6.5.2 Chamber Design Considerations. 6.5.3 Design Examples. 6.5.4 Acceptance Test Procedures. 6.6 Immunity Testing. 6.6.1 Introduction. 6.6.2 Mode-Stirred Test Facility. 6.7 EM System Compatibility Testing. 6.7.1 Design Considerations. 6.7.2 Acceptance Testing. References. 7 The Compact Range Chamber. 7.1 Introduction. 7.2 Antenna Testing. 7.2.1 Prime Focus Compact Range. 7.2.2 Dual Reflector Compact Range. 7.2.3 Shaped Reflector Compact Range. 7.2.4 Compact Antenna Range Absorber Layout. 7.2.5 Acceptance Testing of the Compact Antenna Anechoic Chamber. 7.3 Compact RCS Ranges. 7.3.1 Introduction. 7.3.2 Design Example. 7.3.3 Acceptance Testing. References. 8 Incorporating Geometry in Anechoic Chamber Design. 8.1 Introduction. 8.2 The Tapered Chamber. 8.2.1 Introduction. 8.2.2 Antenna Testing. 8.2.3 Radar Cross-Section Measurements. 8.3 The Double Horn Chamber. 8.3.1 Introduction. 8.3.2 Antenna Testing. 8.3.3 Emissions and Immunity Testing. 8.4 The Missile Hardware-in-the-Loop Chamber. 8.4.1 Introduction. 8.4.2 Design Considerations. 8.4.3 Design Example. 8.4.4 Acceptance Test Procedures. 8.5 Consolidated Facilities. 8.5.1 Introduction. 8.5.2 Design Considerations. 8.5.3 Design Examples. 8.5.4 Acceptance Test Procedures. 8.6 The TEM Cell. 8.6.1 Introduction. 8.6.2 TEM Principles of Operation. 8.6.3 Typical Performance. References. 9 Test Procedures. 9.1 Introduction. 9.2 Absorber Testing. 9.2.1 Introduction. 9.2.2 Testing of Microwave Absorber. 9.2.3 Low-Frequency Testing. 9.2.4 Compact Range Reflector Testing. 9.2.5 Fire-Retardant Testing. 9.3 Microwave Anechoic Chamber Test Procedures. 9.3.1 Introduction. 9.3.2 Free-Space VSWR Method. 9.3.3 Pattern Comparison Method. 9.3.4 X-Y Scanner Method. 9.3.5 RCS Chamber Evaluation. 9.4 EMC Chamber Acceptance Test Procedures. 9.4.1 Introduction. 9.4.2 Volumetric Site Attenuation. 9.4.3 Field Uniformity. 9.5 Shielding Effectiveness. References. 10 Examples of Indoor Electromagnetic Test Facilities. 10.1 Introduction. 10.2 Antenna Testing. 10.2.1 Introduction. 10.2.2 Rectangular Test Chamber. 10.2.3 Tapered Anechoic Chamber. 10.2.4 Compact Range Test Chamber. 10.2.5 Near-Field Test Chamber. 10.3 Radar Cross-Section Testing. 10.3.1 Introduction. 10.3.2 Compact Range Radar Cross-Section Facilities. 10.4 EMC Test Chambers. 10.4.1 Introduction. 10.4.2 Emission Test Chambers. 10.5 Electromagnetic System Compatibility Testing. 10.5.1 Introduction. 10.5.2 Aircraft Systems. 10.5.3 Spacecraft Test Facilities. References. Appendix A: Procedure for Determining the Area of Specular Absorber Treatment. A.1 Introduction. A.2 Fresnel Zone Analysis. Appendix B :Test Region Amplitude Taper. B.1 Introduction. B.2 Antenna Data. Appendix C: Design/Specification Checklists. C.1 Introduction. C.2 The Rectangular Chamber. C.2.1 Introduction. C.2.2 Antenna Testing. C.2.3 RCS Testing. C.2.4 Near-Field Testing. C.2.5 EMI Testing. C.2.6 Isolation Testing. C.2.7 Impedance Testing. C.3 Compact Range. C.3.1 Introduction. C.3.2 Antenna/Radome Testing. C.3.3 RCS Testing. C.4 Shaped Chambers. C.4.1 Introduction C.4.2 Tapered Chamber. C.4.3 Double Horn Chamber. C.4.4 Hardware-in-the-Loop Testing. C.5 Shielding Design Checklist. C.5.1 Introduction. C.5.2 Checklist for Prefabricated Shielding. C.5.3 Checklist for Welded Enclosures. C.5.4 Checklist for Architectural Shielding. C.5.5 Conventional Construction. C.5.6 Fire Protection. References. Glossary. Selected Bibliography. Index. About the Author.

Influence of the technology on the destruction effects of semiconductors by impact of EMP and UWB pulses

Abstract: In this paper the influence of TTL- and CMOS-technology on the destruction effects of semiconductors by impact of EMP and UWB pulses is determined. Different logic devices like NANDs and inverters were exposed to high amplitude transient pulses.

Implantable pacemakers and defibrillators: device overview & EMI considerations

Abstract: Pacemakers and implantable cardioverter defibrillators (ICDs) provide therapy which improves the quality of life for hundreds of thousands of patients and in some cases provide life sustaining therapy. Modern pacemakers and ICDs incorporate hardware and software that helps to mitigate the effects of electromagnetic interference (EMI) on these automatic implantable medical devices (AIMDs). This paper presents a summary of characteristics of pacemakers and ICDs both from the aspect of therapy and electromagnetic compatibility (EMC).

A circuital approach to evaluating the electromagnetic field on rectangular apertures backed by rectangular cavities

Abstract: In this paper, the problem of evaluating the electromagnetic field on rectangular apertures backed by rectangular cavities is investigated. The electromagnetic-field distribution is derived by using a circuital model of an aperture and suitable forcing terms introduced into the equations related to the aperture model. The effects of a rectangular cavity on the aperture-field distribution are assessed by considering the rectangular cavity as a load impedance. The impedance value is obtained by modeling the rectangular cavity as a length of rectangular waveguide back-ended by a short. The distribution of the electromagnetic field on the aperture is used as an exciting source to evaluate, through a modal expansion, the electromagnetic field inside the cavity. Numerical simulations are in a good agreement with both other theoretical models and experimental data.

Calculable field generation using TEM cells applied to the calibration of a novel E-field probe

Abstract: This paper examines the calculable generation of electromagnetic fields for calibration purposes using TEM cells. In order to enlarge the bandwidth the use of a circular coaxial calibration cell (C/sup 3/ cell) is proposed. Based on generalized telegraphist's equations the field is calculated. Results are compared with other common TEM cells (Crawford (1974) cell, GTEM cell). For field measurements a new isotropic field probe is considered. The proposed probe uses only one electrically short dipole with a diode detector and enables the measurement of both the magnitude and the polarization direction of an electromagnetic field. The manufactured probe was calibrated utilizing the C/sup 3/ cell.

Behavioral models of I/O ports from measured transient waveforms

Abstract: This paper addresses the development of accurate and efficient behavioral models of digital integrated circuit ports from measured transient responses. The proposed approach is based on the estimation of parametric models from port voltage and current waveforms. The modeling process is described and applied to the modeling of output ports. Its feasibility is demonstrated by the identification of a real device from actual measurements, and by the comparison of the predicted device response with the measured one.

VHF/UHF radar Part 2: Operational aspects and applications

Abstract: For Part 1 see ibid., vol.14, no.2, p.61-72 (April 2002). Low-frequency radars have the potential to counter stealth efforts and detect low-flying targets beyond the horizon. Part 2 of this paper discusses approaches to target classification and the problems of vulnerability to jamming and operation in a densely populated frequency band. The anti-jamming capabilities of VHF radars are analysed based on measurements conducted with the FHR experimental radar LARISSA and it is demonstrated that electromagnetic compatibility (EMC) with other users of the band can be achieved using a spectral signal-shaping technique. The paper is completed by an overview of possible and existing VHF/UHF radar applications.

A lightning location system in China: its performances and applications

Abstract: This paper describes the largest lightning location system in China-Guang Dong lightning location system (GDLLS), which only locates the electromagnetic fields radiated by individual return strokes in cloud-to-ground flashes. Using information gathered from 14 combined magnetic direction and time-of-arrival finder sensors, the GDLLS provides both real-time and historical lightning data to the electric utility industry. The real-time data include the time of lightning strokes, their location and polarity and an estimate of the peak current. In this paper, the performance of the GDLLS is addressed, including detection efficiency and location accuracy. The potential applications of lightning data collected by the GDLLS are discussed also for electric power utilities in the Guang Dong province.

Electromagnetic pulse environment of cloud-to-ground lightning for EMC studies

Abstract: The characteristics of lightning electromagnetic pulse (LEMP) from individual processes in lightning such as return strokes, preliminary breakdown pulses, pulses associated with the leader process, K-changes and M-changes, the isolated narrow bipolar pulses, and the pulse bursts have been known. However, there is a need for a combined characterization of the total LEMP environment created during the entire duration of lightning. An attempt is made to provide such a description that gives the distribution of the LEMP characteristics, which is important in its ability to interfere with electronic systems, such as peak amplitude, peak time derivative, pulse duration, number of pulses, and time interval between pulses, during the entire duration of a cloud-to-ground lightning. Separate electromagnetic environment characterizations for negative cloud-to-ground lightning and positive cloud-to-ground lightning are proposed, including all the significant LEMP sources. Based on the LEMP characterization, models for negative and positive cloud-to-ground lightning flashes, that could be used in electromagnetic compatibility (EMC) studies are proposed. The electromagnetic environment models for cloud-to-ground lightning can be coupled to the locations of lightning given by the lightning location system to give comprehensive information about the electromagnetic environment at a desired geographical location.

FDTD modeling of heatsink RF characteristics for EMC mitigation

Abstract: Due to their size and complex geometry, large heatsinks such as those used in the power electronics industry may enhance the radiated emissions produced by the circuits employing them. Such enhancement of the radio frequency (rf) radiation could cause the equipment to malfunction or to contravene current EMC regulations. In this paper, the electromagnetic resonant effects of heatsinks are examined using the finite-difference time-domain (FDTD) method and recommendations are made concerning the optimum geometry of heatsinks and the placement of components so as to mitigate potential EMC effects.

Electromagnetic coupling effects in RFCMOS circuits

Abstract: The electromagnetic isolation and coupling characteristics of basic structures, namely metal pads, spiral inductors, and spiral-transistors, implemented in a core-logic CMOS process are evaluated and modeled. The models provide design guidelines on the isolation characteristics of guard-rings and shield layers for RF cross-talk suppression between circuit blocks. The importance of electromagnetic coupling to layout interconnects is demonstrated.

Characterisation of microcontroller susceptibility to radio frequency interference

Abstract: Work in the field of electromagnetic compatibility (EMC), generally concentrating on noise and interference at electronic systems, has recently focused more attention on integrated circuits (ICs). In this work, we mainly focus on immunity of programmable devices to radio frequency interference (RFI). This paper presents various kinds of RFI and how it can be coupled to a digital signal processor (DSP) or micro-controller. A new approach for immunity measurement is introduced and some ways to improve embedded software are proposed.

High-performance inter-PCB connectors: analysis of EMI characteristics

Abstract: Electromagnetic interference (EMI) coupling associated with inter-board connection is investigated. Two experimental techniques, based on |S/sub 21/| measurements, including both common-mode current and near-field measurements, are reported. Both methods, as well as finite difference time domain (FDTD) modeling, were used as experimental and numerical tools for inter-printed-circuit-board (inter-PCB) connector evaluation. The EMI performance of a lab-constructed stacked-card connector, and a commercially available module-on-backplane connector were studied. EMI characteristics of the connectors are demonstrated by investigating a few aspects of the design: type of shield/ground blade for signal return, number and length of ground pins, signal pin designation, etc. Good agreement is achieved between the measurements and the FDTD modeled results.

Nonorthogonal PEEC formulation for time and frequency domain modeling

Abstract: Electromagnetic solvers based on the partial element equivalent circuit (PEEC) approach have proven to be well suited for the solution of combined circuit and EM problems. Most of these tools have been based on rectangular or Manhattan geometries. In this paper we extend the PEEC formulation to the case of nonorthogonal geometries since many practical EMC problems require a more general formulation. The approach in this paper adds geometrical flexibility to PEEC while maintaining the full wave and full spectrum properties.

Electromagnetic interference mitigation by using a spread-spectrum approach

Abstract: We investigate a new technique, referred to as spread-spectrum clock generation (SSCG), for reducing the level of radiated emission from devices with digital clock signals. To calculate the radiated emissions from such devices, we model the radiating geometry and compute the radiated field at a multitude of frequencies by using NEC-4, which is an electromagnetic field solver based on the method of moments (MoM). We consider a variety of modulating profiles for the spread spectrum clock and demonstrate that by using a frequency deviation of only 1%, we can achieve from 10 to 30 dB reduction in the radiated emission levels.

Volume optimization of a PFC flyback structure under electromagnetic compatibility, loss and temperature constraints

Abstract: The aim of this paper is to present an analytical optimization approach of a flyback structure in PFC mode. Indeed, softwares like Saber, Pspice or Simplorer are effective means for the power electronics structure time-domain studies. However, if these structures have an AC input and a high switching frequency (various time scales), time-domain simulation becomes painful and expensive in memory and computing time. The study of EMC performances is also difficult because of the line impedance stabilizer network (LISN) time-constants which comes to penalize the time-domain simulation. In addition, in sizing and optimization process, results in short computing times are needed, so the time-domain simulation may be too time consuming. In this way, the paper proposes to carry out a compromise between the model accuracy and the tool rapidness and recommends the use of analytical models to optimize the passive element volume of a flyback structure by respecting EMC standards, by minimizing the whole losses dissipated in the structure (conduction and switching semiconductor losses, core and copper losses in the transformer) and by constraining the semiconductor junction, the winding and the magnetic circuit temperatures. Firstly, analytical models of the flyback structure for these various optimization aspects are developed, validated by numerical simulation or measures and integrated in an optimization process. Then, the optimization results are presented and validated thanks to a measurement workbench of the flyback structure.

Lightning return-stroke model incorporating current distortion

Abstract: A lightning return-stroke model of transmission-line (TL) type, which incorporates both the attenuation and distortion of the waveform of the propagating current, is proposed. With the proposed model, the influence of the distortion of the propagating current on associated electromagnetic field waveforms is investigated and found to be small.

Coaxial connector and manufacture thereof

Abstract: To provide a coaxial connector which inhibits radiation of an electromagnetic wave to the outside of the device and enables improvements in electromagnetic compatibility (EMC); a method of manufacturing the connector; and a method of inhibiting leakage of an electromagnetic wave using the coaxial connector. A connection section to be connected to a conductive panel is formed from a conductive material. A dielectric substance formed for ensuring insulation of an external conductor from a conductive panel is made thin. A dielectric substance (insulator) acting as a radiation rout of an electromagnetic waveform is sandwiched between two conductors.

Apparatus for noise current reduction in power converters

Abstract: An apparatus for reducing electromagnetic interference due to common mode current in power converters is disclosed. Common mode current flowing through high parasitic capacitance on the load side typically contributes significantly to the electromagnetic interference. In order to reduce the electromagnetic interference the common mode current is reduced by reducing the voltage driving a current through the high parasitic capacitance. A counter-acting voltage source produces a voltage out of phase with the voltage driving the common mode current. Such a counter-acting voltage is obtained with the aid of a winding coupled to the magnetic component in the power converter or by one or more active components. The counter-acting winding is wound with the secondary and primary windings to share the same magnetic core.

A power, packaging, and cooling overview of the IBM eServer z900

Abstract: This paper provides an overview of the power, packaging, and cooling aspects of the IBM eServer z900 design. The semiconductor processor chips must be supported and protected in a mechanical structure that has to provide electrical interconnects while maintaining the chip junction temperature within specified limits. The mechanical structure should be able to withstand shock and vibrations during transportation or events such as earthquakes. The processor chips require electrical power at well-regulated voltages, unaffected by the ac-line voltage and load current fluctuations. The acoustical and electromagnetic noise produced by the hardware must be within the limits set by national regulatory agencies, and the electronic operations must be adequately protected from disruption caused by electromagnetic radiation. For high availability, the power, packaging, and cooling hardware must have redundancy and the ability to be maintained while the system is operating. This paper first overviews the packaging hardware, followed by a description of the first- and second-level packaging, which includes the mother board and the multichip module. Thermal management is discussed from the point of view of both the multichip module and the overall system. Power conversion, management, and distribution are presented next. Finally, the design aspects involved with meeting the requirements of electromagnetic compatibility, acoustics, and immunity to shock, vibration, and earthquakes are discussed.

Estimating DC power bus noise

Abstract: Simultaneous switching noise (SSN) resulting from IC devices can result in significant power bus noise, as well as radiation problems. An approach for estimating the power bus noise spectrum is presented in this paper. The power bus noise caused by digital circuits injecting high-frequency noise onto the DC buses feeding digital devices is calculated The transient current drawn by an IC device is modeled using the load current and the shoot-through current through the power dissipation capacitance. Modeling and experimental results for several digital chips are shown. The modeling agrees well with the experimental results.

ESD field penetration into a populated metallic enclosure a hybrid time-domain approach

Abstract: This paper presents a method for the analysis of the electromagnetic field inside a metallic enclosure populated by printed circuit boards (PCBs) and a comparison with an analogous field into an empty box is also reported. The field source is represented by an electrostatic discharge (ESD) current flowing along a monopole and producing an electric field coupling into a shielded structure through a slot. The model is based on a time domain approach and the solution of the electromagnetic problem is achieved by a hybrid method, characterized by the combination of the method of moments in time domain (MoMTD) and finite difference in time domain (FDTD); this technique allows one to investigate the complex geometry of the problem and to evaluate the strong coupling between the source and the victim structure. All simulated results are validated by measurements.