Investigations on electromagnetic noises and interactions in electronic architectures : a tutorial case on a mobile system

Electromagnetic interactions become critic in embedded and smart electronic structures. The increase of electronic performances confined in a finite volume or support for mobile applications defines new electromagnetic environment and compatibility configurations (EMC). With canonical demonstrators developed for tutorials and EMC experiences, this paper present basic principles and experimental techniques to investigate and control these severe interferences. Some issues are reviewed to present actual and future scientific challenges for EMC at electronic circuit level

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

Susceptibility Scanning as Failure Analysis Tool for System-Level Electrostatic Discharge (ESD) Problems

Susceptibility scanning is an increasingly adopted method for root cause analysis of system-level immunity sensitivities. It allows localizing affected nets and integrated circuits (ICs). Further, it can be used to compare the immunity of functionally identical or similar ICs or circuit boards. This paper explains the methodology as applied to electrostatic discharge and provides examples of scan maps and signals probed during immunity scanning. Limitations of present immunity analysis methods are discussed

Analog-Digital System Modeling for Electromagnetic Susceptibility Prediction

The thesis is focused on the noise susceptibility of communication networks. These analog-mixed signal systems operate in an electrically noisy environment, in presence of multiple equipments connected by means of long wiring. Every module communicates using a transceiver as an interface between the local digital signaling and the data transmission through the network. Hence, the performance of the IC transceiver when affected by disturbances is one of the main factors that guarantees the EM immunity of the whole equipment. The susceptibility to RF and transient disturbances is addressed at component level on a CAN transceiver as a test case, highlighting the IC features critical for noise immunity. A novel procedure is proposed for the IC modeling for mixed-signal immunity simulations of communication networks. The procedure is based on a gray-box approach, modeling IC ports with a physical circuit and the internal links with a behavioural block. The parameters are estimated from time and frequency domain measurements, allowing accurate and efficient reproduction of non-linear device switching behaviours. The effectiveness of the modeling process is verified by applying the proposed technique to a CAN transceiver, involved in a real immunity test on a data communication link. The obtained model is successfully implemented in a commercial solver to predict both the functional signals and the RF noise immunity at component level. The noise immunity at system level is then evaluated on a complete communication network, analyzing the results of several tests on a realistic CAN bus. After developing models for wires and injection probes, a noise immunity test in avionic environment is carried out in a simulation environment, observing good overall accuracy and efficiency

Analysis and mitigation of parallel-plate noise for high-isolation applications

Achieving highs levels of isolation between different functionalities in a PCB can be challenging. One of the major issues is that vertically adjacent planes or area fills in a PCB can form a parallel-plate waveguide with no cutoff frequency and serve as an efficient coupling mechanism between interconnects. Due to the finite size of the conductors, reflections off the edges of these parallel-plate cavities can result in the formation of standing-wave patterns with very high field strengths, resulting in high coupling at certain frequencies. This noise coupling mechanism can be suppressed by connecting the parallel plates together with an adequate amount of vias. However, adjacent power and ground conductors can not be conductively connected together because they are at different DC potentials. As a result, there is no way to eliminate the existence of parallel-plate noise in a power/ground cavity. A fundamental understanding of this problem is needed to determine how it can be mitigated. The first part of the thesis develops a qualitative understanding of the underlying physics of how noise is coupled to the parallel plates from a variety of interconnects and how the noise can spread throughout the design. This discussion is then expanded to more complex geometries that are representative of what could occur in actual designs. Test vehicles are created to study the noise coupling to various interconnects from noise injected into the power distribution network by an amplifier. Parameters affecting the transfer of noise from an amplifier to the power distribution network, such as the addition of capacitors, are then explored. An expression to predict the noise coupling using S-parameter measurements of the PCB and the amplifier is developed. It is demonstrated that results from full-wave electromagnetic simulation can be used to predict the amount of noise coupling before PCB fabrication. General design recommendations are then presented to improve design robustness to the parallel-plate noise --Abstract, page iii

Robust and Efficient Uncertainty Quantification and Validation of RFIC Isolation

Modern communication and identification products impose demanding constraints on reliability of components. Due to this statistical constraints more and more enter optimization formulations of electronic products. Yield constraints often require efficient sampling techniques to obtain uncertainty quantification also at the tails of the distributions. These sampling techniques should outperform standard Monte Carlo techniques, since these latter ones are normally not efficient enough to deal with tail probabilities. One such a technique, Importance Sampling, has successfully been applied to optimize Static Random Access Memories (SRAMs) while guaranteeing very small failure probabilities, even going beyond 6-sigma variations of parameters involved. Apart from this, emerging uncertainty quantifications techniques offer expansions of the solution that serve as a response surface facility when doing statistics and optimization. To efficiently derive the coefficients in the expansions one either has to solve a large number of problems or a huge combined problem. Here parameterized Model Order Reduction (MOR) techniques can be used to reduce the work load. To also reduce the amount of parameters we identify those that only affect the variance in a minor way. These parameters can simply be set to a fixed value. The remaining parameters can be viewed as dominant. Preservation of the variation also allows to make statements about the approximation accuracy obtained by the parameter-reduced problem. This is illustrated on an RLC circuit. Additionally, the MOR technique used should not affect the variance significantly. Finally we consider a methodology for reliable RFIC isolation using floor-plan modeling and isolation grounding. Simulations show good comparison with measurements

Radiation noise source modeling and near-field coupling estimation in RF interference

With increasing complexities and shrinking size of modern electronic devices, the near-field RF interference issues are becoming challenging for RF-digital mixed circuit design. Predicting the coupling from digital module to RF antennas and mitigating RF interference is important to the system performance. The ultimate goal of this study is to address the desensitization issues existing in modern electronic devices that have mixed high speed digital-RF circuits, such as cellphone and wearable devices. In order to estimate the near-field noise coupling from digital module to RF antennas, the noise source is anticipated to be replaced by its equivalent radiation model which can facilitate the near-field coupling analysis. This thesis focuses on modeling of radiation noise source and its application in RF interference applications. Two methods are proposed, equivalent dipole moment model and Huygens\u27s equivalent model. The methodology of both methods will be introduced and later validated with full-wave simulation and measurement. Dipole moment model is extracted by Least-square and improved with global optimization, while Huygens\u27s equivalent model is constructed in full-wave simulation tool. With equivalent noise source model, the near-field coupling between radiation noise source and RF antennas are estimated by either direct simulation or reciprocity theorem. Field data is obtained by near-field scanning with phase information. Measurement data shows good correlation and consistence for noise source modeling and near-field coupling --Abstract, page iii

Advancement on the Susceptibility of Analog Front-Ends to EMI

L'abstract è presente nell'allegato / the abstract is in the attachmen

Far-field prediction using only magnetic near-field scanning and modeling delay variations in CMOS digital logic circuits due to electrical disturbances in the power supply

The first topic of this dissertation is far-field prediction using only magnetic near-field scanning. Near-field scanning has been used extensively for the far-field estimation of antennas. Applied to electromagnetic compatibility (EMC) problems, near-field scanning has been used to estimate emissions from both integrated circuits (ICs) and printed circuit boards (PCBs). Interest in applying far-field predictions using near-field to EMI/EMC problems has recently grown. To predict the far-field emissions from a PCB in the top half space, the near-field data on a planar surface above PCB usually is sufficient. However, near-field measurement on only one planar surface may not be enough to predict the far-field radiation of three-dimensional structures. The near-field on an enclosed Huygens\u27s surface may be preferred for near-field scanning when predicting the far-field radiation associated with the EMI problems of some complex structures. Based on the equivalence theorem (Huygens\u27s principle), both equivalent electric current obtained from the tangential magnetic field and equivalent magnetic current obtained from the tangential electric field are needed to perform far-field transformation from near-field data. However, designing electric field probes for tangential components is more difficult than designing magnetic field probes. As a result and in the interest of reducing scan time, far-field transformation based only on magnetic field near-field measurements is preferred. In the first paper, a novel method is proposed to predict the far-field radiation using only the magnetic near-field component on a Huygens\u27s box. The proposed method was verified with two simulated examples and one measurement case. The effect of inaccuracy of magnetic field and the incompleteness of the Huygens\u27s box on far-field results is investigated in this paper. The proposed method can be applied for arbitrary shapes of closed Huygens\u27s surfaces. Only the tangential magnetic field needs to be measured. And it also shows good accuracy and robustness in use. Measuring only the magnetic field cuts the scan time in half. The second topic of this dissertation is modeling delay variations in CMOS digital logic circuits due to electrical disturbances in the power supply. Electronic designers go to considerable effort to minimize the susceptibility of electronic systems against electromagnetic interference. For many systems, the component which fails is an integrated circuit (IC). Susceptibilities are typically found through testing, which is expensive, time consuming, and does not always uncover problems that are encountered in the field. While IC-level testing helps to establish the operational limits of an IC, testing rarely ensures the IC can withstand all interferences, even within the specified limits. Even when a problem is found, the engineer often does not know why a problem was caused or the best way to prevent the problem in the future. Solving problems through trial and error cannot be done as it is at the system level, because of the prohibitive cost of manufacturing and testing multiple versions of the IC. The IC engineer must build the IC to be robust on the first design cycle. IC failures may be caused by a hard failure of the IC, for example, due to latch-up or permanent damage to an I/O pin, or may be caused by a soft failure, where incorrect data is read from I/O, internal logic, and/or memory. Soft errors that occur within the logic and/or memory components of the IC can be particularly difficult to deal with since errors associated with these components are much more diverse and complex than those associated with I/O. One common reason for soft errors is that a change in the power supply voltage causes a change in the propagation delay through internal logic or the clock tree, so that the clock edge arrives at a register before valid data and an incorrect logic value is stored at the register. While methods are available to predict the level of voltage fluctuation within the IC from an external electromagnetic event, predicting when a failure will occur as a result of the event is challenging. Methods are developed in the second paper and third paper to help predict these soft failures, by predicting the change in the propagation delay through logic during an electromagnetic disturbance of the power supply. In the second paper, an analytical delay model was developed to predict propagation delay variations in logic circuits when the power supply is disturbed by an electromagnetic event. Simulated and measured results demonstrate the accuracy of the approach. Four different types of logic circuits were tested, verifying that the proposed delay model can be applied to a wide range of logic circuits and process technologies. Analytical formulas were developed to predict the clock period variation in integrate circuit when the power supply is disturbed by an electromagnetic event in the third paper. The proposed formulas can be seen as a clock jitter model. The clock jitter due to the power supply variation can be estimated by the proposed propagation delay model. It is more meaningful, however, to estimate the clock period variation rather than the delay variation for one clock edge, because it is clock period which affects if a soft error will happen or not. Simulated results using Cadence Virtuoso demonstrate the validity and accuracy of the proposed approach. Three different types of noise were used to disturb the power supply voltage, verifying that the proposed model can be applied to a wide range of disturbance of power supply. Many electromagnetic events cause soft errors in ICs by momentarily disturbing the power supply voltage. The proposed model can be helpful for predicting and understanding the soft errors caused by these timing changes within the logic --Abstract, page iv

An Improved dipole-moment model based on near-field scanning for characterizing near-field coupling and far-field radiation from an IC

Radio Frequency Interference (RFI) problems are critical issues in wireless platform design. The accurate noise model of integrated circuits (ICs) is needed to help designers to diagnose and predict RFI problems. In this dissertation, an improved IC radiated emission model based on near-field measurements is proposed. The regularization technique and the truncated SVD method are employed together with the least square method to calculate the dipole moments from the near-field data. This dipole model has clear physical meaning: the electric and magnetic dipoles represent the voltage and the current in the circuit, respectively. One application of this dipole model is the prediction of heat sink radiation. In order to accurately predict the fields excited by a heat sink, an approach is proposed in this paper to include the exact excitation of the heat sink, which is described by some dipole moments constructed from the near-field scanning of the integrated circuit beneath the heat sink. Another contribution of the work is the proposal of effective dielectric properties of layered media for cavity model applications. With the effective properties. the cavity model can be generalized for either parallel plates or metal enclosures containing multiple dielectric layers. In the fourth paper a unified s-parameter (multimode s-parameter) representation for a multiport passive structure is proposed. Both mixed-mode and single-ended s-parameters arc included in the unified representation, which makes it more convenient to characterize structures --Abstract, page iv