Time-domain green's function-based parametric sensitivity analysis of multiconductor transmission lines

We present a new parametric macromodeling technique for lossy and dispersive multiconductor transmission lines. This technique can handle multiple design parameters, such as substrate or geometrical layout features, and provide time-domain sensitivity information for voltages and currents at the ports of the lines. It is derived from the dyadic Green's function of the 1-D wave propagation problem. The rational nature of the Green's function permits the generation of a time-domain macromodel for the computation of transient voltage and current sensitivities with respect to both electrical and physical parameters, completely avoiding similarity transformation, and it is suited to generate state-space models and synthesize equivalent circuits, which can be easily embedded into conventional SPICE-like solvers. Parametric macromodels that provide sensitivity information are well suited for design space exploration, design optimization, and crosstalk analysis. Two numerical examples validate the proposed approach in both frequency and time-domain

Investigation of Radiation Characteristics of Microstrip Etches

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / N00014-90-J-127

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method

Plasmonic waveguides and nano-antennas for optical communications

The field of plasmonics has received great attention during the past years. Plasmonic devices are characterized by their small electrical size which enabled researchers to overcome the challenge of the size mismatch between the bulky photonic devices and the small electronic circuits. Plasmonic metals are characterized by their lossy dielectric nature which is different from the highly conductive classical metals. Consequently, the design of plasmonic devices necessitates upgrading the existing solvers to take into consideration their material properties at the optical frequency range. In this thesis, a plasmonic transmission line mode solver is developed in which the propagation characteristics of plasmonic transmission lines/waveguides are calculated. More specifically, the solver calculates the propagation constant, losses, and mode profile(s) of the propagating mode(s). The transmission lines can have any topology and are assumed to be placed within a stack of flat layers. The solver is developed using the Method of Moments technique which is characterized by its tremendously decreased number of unknowns compared to the finite element/difference methods leading to much faster calculation time. The solver is tested on several plasmonic transmission lines of various topologies, number of metallic strips and/or surrounding media. These transmission lines include rectangular strip, circular strip, triangular strip, U-shaped strip, horizontally coupled strips, and vertically coupled strips. The obtained results are compared with those calculated by the commercial tool “CSTâ€. Very good agreement between both solvers is achieved. The second line presented within this thesis is concerned with the design of plasmonic wire-grid nano-antenna arrays. The basic element of this array is a nano-rod, whose propagation characteristics are first obtained using the developed solver. The arrays are then optimized using “CSTâ€. Within the context of this thesis, three nano-antenna arrays are proposed: a five-element wire-grid array, an eleven-element wire-grid array, and a novel circularly polarized wire-grid array. All of these arrays have high directivity and are suitable for inter-/intra-chip optical communication, where they replace the losing transmission lines

Statistical modeling of frequency responses using linear Bayesian vector fitting

This article presents a Bayesian extension of the vector fitting (VF) procedure for rational approximation of frequency-domain responses. The proposed method treats the linear part of VF in a Bayesian way, while propagating distributions through the nonlinear part by sampling. As such, it is capable of providing data-driven uncertainty information along with the rational fit. The Bayesian VF technique is applied to two realistic design examples, a double folded stub filter and a RAM memory channel, demonstrating its validity and highlighting three potential applications of this novel framework

Guideline for Numerical Electromagnetic Analysis Method

The aim of this document is to provide an extended description and application guide of methods belonging to the so-called Numerical Electromagnetic Analysis (NEA) applied to the calculation of electromagnetic transients in power systems. As known, the accurate computation of electromagnetic transients is a fundamental requirement of several studies in the area of power systems. Lightning and switching studies are, for instance, typical subjects where the accuracy of transient’s computation has a direct influence to the proper sizing of components like insulators and breakers. Traditional approaches adopted since now were based on the combination of circuit and transmission lines theories. These approaches, analytically and numerically validated by numerous contributions to the literature, rely on specific assumptions that are inherently relaxed by NEA methods. Indeed, NEA methods mostly rely on the numerical solution of the full-wave Maxwell’s equations and, in this respect, the assessment of their accuracy, as well as the description of the various numerical methodologies, have motivated the preparation of this Technical Brochure. In this context, this guide will first discuss the general aspects and limitations associated to classical circuit and transmission lines theories. In particular, the guide will make reference to the modelling approaches used to represent the most typical power system components, like transmission lines, grounding systems, towers etc., within EMTP-like simulation tools (Electromagnetic Transient Program). A first comparison with the most typical NEA methods is presented in order to discuss the main differences and better support the contents of this guide. Then, the guide focuses on the analytical formulation of the most used NEA methods like, the Finite-Difference Time-Domain (FDTD), the Transmission Line Matrix ‘TLM’, the Finite-Element Method in Time Domain (FEMTD), the Method of Moment (MoM) and the Partial Element Equivalent Circuit (PEEC) method. A further remark refers to the comparative analysis of NEA vs EMTP-like simulation approaches. Such an assessment, addressed in this document in various sections, aims at stressing the advantages and drawbacks of both methods. Indeed, NEA methods, although characterized, in general, by better accuracies, result into non-negligible computation times that require the availability of specific computation environments. Such a characteristic is due to the inherent numerical complexity of NEA solvers that require the treatment of large amount of data that, additionally, have an influence on the results accuracy. To this end, the last part of the guide refers to the benchmarking of the various NEA methods by means of typical test cases. In this respect, the members of the Cigré WG C4.501 agreed to include a specific section of the brochure aimed at providing the NEA-computed electromagnetic transients with reference to the most typical test cases like: (i) lightning surge calculation in substations, (ii) influence of grounding on lightning surge calculation in substations, (iii) surge voltages on overhead lines, (iv) lightning-induced surges on distribution lines, (v) LEMP and induced surges calculation in overhead lines above a lossy ground and (vi) simulations of very fast transients (VTFs) in GIS. Additionally, as NEA methods represent power tools for the computation of parameters of power systems components, the guide has also provided benchmarking examples for the following assessments: (a.) surge characteristics of transmission towers, (b.) surge characteristics of grounding electrodes, vertical grounding rods, horizontal grounding electrode and complex grounding configurations, (c.) influence of grounding on surge propagation in overhead transmission lines, (d.) propagation characteristics of PLC signals along power coaxial cables, (e.) lightning surge characteristics of wind-turbine towers

The analysis and modeling of fine pitch laminate interconnect in response to large energy fault transients

In embedded applications, the miniaturization of circuitry and functionality provides many benefits to both the producer and consumer. However, the benefits gained from miniaturization is not without penalty, as the environmental influences may be great enough to introduce system failures in new or different modes and effects;Of particular interest within this research is the effect of fault transients in reduced geometries of printed circuit card interconnect, commonly referred to as fine pitch laminate interconnect. Whereas larger geometries of conductor trace width and spacing may have been immune to circuit failure at a given fault input, the reduction of the trace geometry may introduce failures as the insulating effect of the dielectric is compromised to the point where arcing occurs;To address this concern, a circuit card was designed with fine pitch laminate features in microstrip, embedded microstrip, and stripline constructions. Various trace widths and separations were tested for structural integrity (presence of arcing or fusing) at voltage extremes defined in avionics standard. The specific trace widths in the test were 4 mils, 6 mils, 8 mils, and 12 mils, with the trace separation in each case equal to the trace widths. The results of the tests and methods to artificially improve the integrity of the interconnect are documented, providing a clear region of reliable operation to the designers and the engineering community;Finally, the construction of the interconnect and the results from the test were combined to create an empirical model for circuit analysis. Created for the Saber simulator, but readily adaptable to Spice, this model will describe high-speed operation of a propagating signal before breakdown, and uses data from the experiment to calculate threshold values for the arcing breakdown. The values for the breakdown voltages are correlated to the experimental data using statistical methods of weighted linear regression and hypothesis testing

Advanced Electromagnetic Waves

This book endeavors to give the reader a strong base in the advanced theory of electromagnetic waves and its applications, while keeping pace with research in various other disciplines that apply electrostatics/electrodynamics theory. The treatment is highly mathematical, which tends to obscure the principles involved