G. Antonini

Enhancing feature selective validation (FSV) interpretation of EMC/SI results with grade-spread

The comparison of high volumes of potentially visually complex data requires an automated method to support the engineers involved. The Feature Selective Validation (FSV) method is becoming increasingly popular as a solution to this. This paper reports on an enhancement to the method which uses the confidence in the FSVs component measures to provide a means of relative weighting of them and thus improving the ability of the method to satisfy one of the key criteria: mimicking human response. This is a good analogue to how the data would be considered by individuals. The trend components of the data are compared to provide an Amplitude Difference Measure (ADM) and the feature components are compared to provide a Feature Difference Measure (FDM). These two components can be viewed as point-by-point results (allowing direct comparison with the original data) in order to identify the precise locations of the elements leading to poor comparisons or as single summary numbers allowing an overall level of agreement to be obtained. The point-by-point values and the summary values can be combined (treating them as independent) to give a Global Difference Measure, a headline measure of the quality of agreement.

Applications of FSV to EMC and SI data

This paper is concerned with the usability of the feature selective validation (FSV) method for comparing validation data. It addresses how it can help in the validation process and how the resulting validation data can be interpreted. It does this by considering two different case studies. The first considers two approaches to modeling electric fields in an equipment rack, and the second compares a Spice model for coupled circuit boards with a reference full wave model. The paper concludes that while the single value summary metrics are helpful to give an overall level of agreement, the detailed point-by-point information is very helpful when considering how to improve the models or measurements involved.

Extension of the partial element equivalent circuit method to non-rectangular geometries

We consider the extension of the partial element equivalent circuit approach to non-rectangular problems. This extension is important for printed circuit boards and other EMI problems where non-orthogonal geometries are present. We give a formulation which is a natural extension of the model for orthogonal conductors. The formulation is chosen in such a way that the advantages of the conventional PEEC models are preserved.

Speed-up of PEEC method by using wavelet transform

The partial element equivalent circuit (PEEC) method has been applied for the time and frequency domain modeling of many different EMI problems. This method is especially suitable for the solution of problems which involve mixed circuit and electromagnetic parts as they occur in a VLSI system. An important issue for all modeling techniques is the faster solution of larger problems of this type. The makes the solution of more realistic EMC problems possible. We explore the application of the wavelet transform to the PEEC circuit matrix in both the time and the frequency domains. Further, examples are given for the speed-up due to the wavelet transform for both domains.

Harten's scheme for PEEC method

The analysis of realistic EMC problems is time and memory consuming. When using integral methods this results in the solution of very large systems that must be solved very carefully because of their ill conditioning. This paper presents a class of multiresolution representations based on Hartens point value multiresolution framework which is used to improve the spectral properties of matrices arising from the partial element equivalent circuit (PEEC) method. The proposed representation allows the solution being obtained more efficiently by means of iterative solvers that are needed for very large systems.

Cross-SSN analysis in multilayer printed circuit boards

As digital circuits became faster and more power is involved, direct coupling in multilayer printed circuit boards (PCBs) among power (PWR) planes becomes a major concern for signal integrity (SI) and electromagnetic interference (EMI). Aim of this paper is to show how an electromagnetic wave can propagate between planes and therefore induce noise on the signals crossing the planes pairs through vias eventually radiate from the edge of the board. More specifically our study focuses on the analysis of the noise which propagates from a power plane to another power plane due to their proximity, named cross-simultaneous switching noise (X-SSN). This effect can be mitigated by a careful analysis of the location of PWR and ground (GND) planes in the board stack-up which avoid the contiguity of two PWR planes. A test board is built and measurements are performed. These measurements are also compared with three dimensional numerical results.

Validation of equivalent circuits extracted from S-parameter data for eye-pattern evaluation

S-parameter circuit model extraction is usually characterized by a trade off between accuracy and complexity. Trading one feature for another may or may not affect the goodness of the reconstructed S-parameter data, which are obtained from frequency domain simulations of the models extracted. However, the ultimate test for the validity of these equivalent circuit representations should be left to eye-diagram simulations, which provide useful insights, from an SI point of view, about the degradation of the signal, as it travels through the system. Physics based simplification procedures can be used to tune the models and achieve less complexity, whereas the comparisons of the eye-diagrams may help to quantify the goodness of all these circuits extracted. In fact, the most accurate model is not necessary the best to be used.

Experimental validation of circuit models for bulk current injection (BCI) test on shielded coaxial cables

In order to validate, by means of measurement, some existing equivalent circuit models for the bulk current injection (BCI) test, a procedure is proposed to develop a proper circuit model for the injection clamp and the obtained circuit is introduced into the global one representing the overall cable. A suitable experimental set-up has been built and used. The measured induced voltages at the terminations of shielded coaxial cables are compared with those computed by the equivalent circuit. Upper and lower bounds are quantified in order to assess the order of accuracy of the predicted results.

Electromagnetic interferences on implantable medical devices onboard of high speed trains

This paper reports a study of electromagnetic interferences on implantable medical devices (pacemakers) on board of high speed trains due to magnetic fields generated by filters along the tracks. The magnetic flux density is computed by using different numerical techniques and compared with experimental data; further, the voltage induced on a pacemaker is computed. An analysis of the Standards regarding interferences in pacemakers is carried out leading to find the limit values of flux density and induced voltage which may cause a malfunctioning of such devices. Keywords-implantable medical devices, electromagnetic interferecnes, high speed trains.

Toward improved time domain stability and passivity for full-wave PEEC models

It is well known that time domain integral equation techniques may suffer from stability problems and frequency domain models may provide non-passive results. A main source of these issues is the delay of the coupled elements. In the classical Partial Element Equivalent Circuit (PEEC) method, a single delay was used for each couple of partial element which results in a delay differential equation with reduced stability and accuracy. In this paper, we consider multiple delay coefficients which can be used for both the time and frequency domain. Also, filters are introduced which remove unwanted eigenvalues or resonances in the partial element couplings. This can substantially improve the response of the frequency domain and the time domain models. Stability improvements also means passivity improvements.