Modeling and optimal design of shorting vias to suppress radiated emission in high-speed alternating PCB planes

An analytical mode analysis of vias in the multilayered printed-circuit-board periphery is developed to suppress the electromagnetic radiation induced by ground bounce. After separating the even and odd modes in alternating planes, the far-field radiation of parallel plates is derived using Huygens' principle. It is mainly contributed by the odd mode excitation, while the even mode sets a lower bound on the radiation level from the system when shorting vias are inserted between alternating ground plates. For the odd-mode radiation, a canonical problem is then constructed and analytically solved by applying image theory. Based on that, a systematic approach to achieve the optimum suppression design is developed for the various geometry parameters of the shorting vias, including the pitch, radius, and distance to the board edge. Full-wave simulation and measurement are also presented and the good agreement with the theoretical prediction validates the correctness and efficiency of the present analysis and design

Reduction of EMI due to common mode current using common mode filter or lossy material

This thesis consists of four papers. In the first paper, two new common mode filter structures were designed, fabricated, and measured. A sandwich-type EBG structure that resonates at the desired filter frequency is designed to suppress common mode filter on differential signals. The new filters are placed on top of the PCB as a surface-mount component, instead of being implemented within the PCB stackup. The total radiated power (TRP) of the implemented filter is investigated and discussed. RF absorbing material and traditional shielding are considered to reduce the TRP. In the second paper and third paper, new PCB-embedded common mode filters are designed and investigated. Based on a quarter-wavelength resonator, an inter-digital structure is designed having an electrical size of only 0.15 λ x 0.065 λ, where λ is the effective wavelength in the CM filter. Its interdigital structure is also capable of suppressing higher order harmonics of the CM signal and can be used for USB 3.0 to mitigate electromagnetic interference. Further, a novel broadband suppression structure is described that uses magnetically lossy material to suppress the CM signal from 4.6 to 20 GHz without strongly affecting the intended differential signal. In the fourth paper, a methodology for validating the parameters of magnetic absorbing materials was developed. The microstrip line test can be recommended as an easy-to-implement validation method for the measured material parameters. The heat sink model and simulation comparison has also been investigated to determine the radiation mitigation with lossy materials --Abstract, page iv

Electromagnetic Interference and Compatibility

Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

ELECTROMAGNETIC BANDGAP STRUCTURES FOR BROADBAND SWITCHING NOISE MITIGATION IN HIGH-SPEED PACKAGES

For the past two decades, silicon-based complementary metal-oxide semiconductor (CMOS) technology and circuits have been advancing along an exponential path of shrinking device dimensions, increasing density, increasing speed, and decreasing cost. Electronic design complexity is in constant acceleration and new designs have to incorporate new features, which inevitably will require faster processing time. In recent years this acceleration rate has drastically decreased because of various constraints, such as static power dissipation due to leakage current, the effect of wires and interconnects and the decreased immunity of modern devices to noise, interference and voltage fluctuations on their Power Distribution Network (PDN). Lowering the power supply voltages and hence the power consumption of a single transistor, has been possible due to the fact that these new technologies are able to provide smaller and faster transistors with lower threshold levels. The benefits associated with lowering the threshold levels of the transistors used in a given device comes at a high-price, specifically the decrease of immunity of such device to noise and fluctuations of the power supply voltage. The research work carried out in this dissertation, addresses the concept of embedding Electromagnetic Bandgap (EBG) structures in conventional power distribution networks in order to increase the immunity of the circuits that feed from such networks to noise and voltage fluctuations. Underlying theories of Embedded EBG (EEBG) structures and design methodologies are presented. Various design concepts, based on simulations, measurements and different modeling techniques developed during this research work are presented. The accuracy of these methods is analyzed by comparing results of these techniques with experimental results. Also, this work shows that EEBG structures are not only very effective in the suppression of switching noise in high-speed circuit but also they suppress Electromagnetic Interference (EMI) caused by such switching and they provide increased immunity for their PDN to external sources of noise. Finally new EEBG configurations, topologies and miniaturized structures are introduced that overcome the limitations of current switching noise mitigation techniques, including initial EEBG designs to provide immunity against high-bandwidth noise, voltage fluctuations and radiation, new EEBG configurations, topologies and miniaturized structures are introduced and their efficacy is demonstrated. The novel designs developed during this research provide noise mitigation over a wide range of frequencies, and also extends the suppression frequency range into the sub-gigahertz region, only using a single EBG design with smaller patches than those used in previous works

Metamaterials for Decoupling Antennas and Electromagnetic Systems

This research focuses on the development of engineered materials, also known as meta- materials, with desirable effective constitutive parameters: electric permittivity (epsilon) and magnetic permeability (mu) to decouple antennas and noise mitigation from electromagnetic systems. An interesting phenomenon of strong relevance to a wide range of problems, where electromagnetic interference is of concern, is the elimination of propagation when one of the constitutive parameters is negative. In such a scenario, transmission of electromagnetic energy would cease, and hence the coupling between radiating systems is reduced. In the first part of this dissertation, novel electromagnetic artificial media have been developed to alleviate the problem of mutual coupling between high-profile and ow-profile antenna systems. The developed design configurations are numerically simulated, and experimentally validated. In the mutual coupling problem between high-profile antennas, a decoupling layer based on artificial magnetic materials (AMM) has been developed and placed between highly-coupled monopole antenna elements spaced by less than Lambda/6, where Lambda is the operating wavelength of the radiating elements. The decoupling layer not only provides high mutual coupling suppression (more than 20-dB) but also maintains good impedance matching and low correlation between the antenna elements suitable for use in Multiple-Input Multiple-Output (MIMO) communication systems. In the mutual coupling problem between low-profile antennas, novel sub-wavelength complementary split-ring resonators (CSRRs) are developed to decouple microstrip patch antenna elements. The proposed design con figuration has the advantage of low-cost production and maintaining the pro file of the antenna system unchanged without the need for extra layers. Using the designed structure, a 10-dB reduction in the mutual coupling between two patch antennas has been achieved. The second part of this dissertation utilizes electromagnetic artificial media for noise mitigation and reduction of undesirable electromagnetic radiation from high-speed printed-circuit boards (PCBs) and modern electronic enclosures with openings (apertures). Numerical results based on the developed design configurations are presented, discussed, and compared with measurements. To alleviate the problem of simultaneous switching noise (SSN) in high-speed microprocessors and personal computers, a novel technique based on cascaded CSRRs has been proposed. The proposed design has achieved a wideband suppression of SSN and maintained a robust signal integrity performance. A novel use of electromagnetic bandgap (EBG) structures has been proposed to mitigate undesirable electromagnetic radiation from enclosures with openings. By using ribbon of EBG surfaces, a significant suppression of electromagnetic radiation from openings has been achieved

A Comprehensive Study on Printed Circuit Board Backdoor Coupling in High Intensity Radiated Fields Environments

Due to the prevalence of unintentional electromagnetic interference (EMI) and the growth of intentional electromagnetic interference (IEMI) or high power microwave (HPM) sources, it is now more important than ever to understand how electronic systems are affected by high intensity radiated fields (HIRF) environments. Both historic events and experimental testing have demonstrated that HIRF environments are capable of disrupting and potentially damaging critical systems including but not limited to civil and military aircraft, industrial control systems (ICS), and internet of things (IoT) devices. However, there is limited understanding on the complex electromagnetic interactions that lead to such effects. This study provides unique insight into the backdoor coupling mechanisms associated with printed circuit boards (PCBs) as well as design techniques for reducing electromagnetic coupling in HIRF environments. Among existing literature, there is very little quantification of PCB coupling leading to multiple gaps in understanding. In this study, both PCB plane coupling and PCB trace coupling are explored under various conditions using 3D full-wave electromagnetic modeling and experimental testing. Data is provided for each individual technique as well as combinations of techniques which show greater immunity. Through this comprehensive study on PCB backdoor coupling, this work demonstrates that simple and explainable techniques can be incorporated into multi-layer PCB designs to mitigate coupling in HIRF environments. Additionally, variations in PCB layout as well as plane wave angle of incidence and polarization are explored to ensure that the conclusions are broadly applicable. It is expected that the information in this study as well as future work in this area will enable hardening design guidelines in order to reduce coupling and therefore better protect systems in such harsh electromagnetic environments

Marshall Space Flight Center Electromagnetic Compatibility Design and Interference Control (MEDIC) handbook

The purpose of the MEDIC Handbook is to provide practical and helpful information in the design of electrical equipment for electromagnetic compatibility (EMS). Included is the definition of electromagnetic interference (EMI) terms and units as well as an explanation of the basic EMI interactions. An overview of typical NASA EMI test requirements and associated test setups is given. General design techniques to minimize the risk of EMI and EMI suppression techniques at the board and equipment interface levels are presented. The Handbook contains specific EMI test compliance design techniques and retrofit fixes for noncompliant equipment. Also presented are special tests that are useful in the design process or in instances of specification noncompliance

Avionics system design for high energy fields: A guide for the designer and airworthiness specialist

Because of the significant differences in transient susceptibility, the use of digital electronics in flight critical systems, and the reduced shielding effects of composite materials, there is a definite need to define pracitices which will minimize electromagnetic susceptibility, to investigate the operational environment, and to develop appropriate testing methods for flight critical systems. The design practices which will lead to reduced electromagnetic susceptibility of avionics systems in high energy fields is described. The levels of emission that can be anticipated from generic digital devices. It is assumed that as data processing equipment becomes an ever larger part of the avionics package, the construction methods of the data processing industry will increasingly carry over into aircraft. In Appendix 1 tentative revisions to RTCA DO-160B, Environmental Conditions and Test Procedures for Airborne Equipment, are presented. These revisions are intended to safeguard flight critical systems from the effects of high energy electromagnetic fields. A very extensive and useful bibliography on both electromagnetic compatibility and avionics issues is included

Airborne UHF Radar for Fine Resolution Mapping of Near Surface Accumulation Layers in Greenland and West Antarctica

The usefulness of accurate, fine resolution accumulation layer measurements over central Greenland and West Antarctica is significant for the improvement of ice sheet models. These models are critical to both global climate models as well as understanding sea level rise. Previously developed accumulation layer radars were used as templates for the current single channel system. Improvements were incorporated including increased output power, increased receiver sensitivity, single antenna operation, and reduced susceptibility to external noise sources. Steps were also taken to reuse previously purchased components to reduce development costs. Externally developed Vivaldi and elliptical dipole antennas were utilized. Collected data shows the system is capable of measuring layering to a depth of nearly 300 m in most dry snow regions of Greenland and West Antarctica with a resolution of ~0.5 m. Future revisions will focus on reducing size and weight, as well as incorporate multiple receive channels to allow for clutter rejection algorithms to be applied; this will allow for viable data collection in percolation and wet snow zone of major ice sheets

EMC in Power Electronics and PCB Design

This dissertation consists of two parts. Part I is about Electromagnetic Compatibility (EMC) in power electronics and part II is about the Maximum Radiated Electromagnetic Emissions Calculator (MREMC), which is a software tool for EMC in printed circuit board (PCB) design. Switched-mode power converters can be significant sources of electromagnetic fields that interfere with the proper operation of nearby circuits or distant radio receivers. Part I of this dissertation provides comprehensive and organized information on the latest EMC developments in power converters. It describes and evaluates different technologies to ensure that power converters meet electromagnetic compatibility requirements. Chapters 2 and 3 describe EMC noise sources and coupling mechanisms in power converters. Chapter 4 reviews the measurements used to characterize and troubleshoot EMC problems. Chapters 5 - 8 cover passive filter solutions, active filter solutions, noise cancellation methods and reduced-noise driving schemes. Part II describes the methods used, calculations made, and implementation details of the MREMC, which is a software tool that allows the user to calculate the maximum possible radiated emissions that could occur due to specific source geometries on a PCB. Chapters 9 - 13 covers the I/O coupling EMI algorithm, Common-mode EMI algorithm, Power Bus EMI algorithm and Differential-Mode EMI algorithm used in the MREMC