RESEARCH
 

RESEARCH

Research Activities

This page outlines the main research activities of our group. If you are interested, follow the links to find more detailed descriptions and relevant publications. Please feel free to contact us if you need specific information and the publication section for information regarding specific projects ongoing in the EMC group.

Macromodeling of Electrical Interconnects and Packages

This is one of the main research activities of our group at present. It is aimed at providing the designers of electronic systems with accurate and efficient models of electrical interconnections. These may include connectors, packages, transitions, junctions and discontinuities, vias on printed circuit boards, and also transmission lines. All these structures have a significant influence on the signals that propagate through them. Although several modeling strategies are available even in commercial CAD tools, they result often inadequate for the extended bandwidth required by the ever-increasing clock frequencies, now well into the GHz range. Our research activity is focused on the development of efficient macromodeling procedures leading to mathematical/circuit models characterized by a good accuracy and by a reduced complexity. This involves theoretical development of the macromodeling algorithms and their validation on realistic structures.

Transmission Lines and Cables

Transmission-Line structures are ubiquitous in all electronic systems at any scale, from on-chip, to printed circuit boards and cables. These structures are intended as guiding paths for electrical signals, but unfortunately they may provide also good coupling mechanisms, allowing unwanted signals to interfere with the desired ones. In fact, Signal Integrity issues are of fundamental importance in any electronic system. Our research activities are focused on many aspects, including line characterization, crosstalk and field coupling analysis, dispersion, losses, nonuniformities, and efficient frequency and time-domain simulation, including macromodel generation for commercial solvers.

Macromodeling of Devices for High-Speed Digital Applications

The transmission of digital signals always requires at least one driver and one receiver. The characteristics of these devices depend on the application and on the technology. However, they are always made of transistors and built in integrated circuits, and therefore are nonlinear and dynamic elements when looked at their interface ports. Unfortunately, the nonlinear and dynamic effects are important for signal propagation, since any realistic Signal Integrity analysis must take them into account. Accurate transistor-level models in standard circuit simulation environment like SPICE are usually available to designers, but unfortunately these models are so complex that they result practically unusable for systematic analyses. This is the reason why our group has dedicated much efforts in the development of accurate and efficient macromodels for drivers and receivers, including all relevant effects for Signal Integrity issues.

Fields, Radiation, and Numerical Techniques

Electromagnetic fields in complex environments are the responsible for many challenging problems in EMC. Prediction of these fields is often very difficult, and full-wave solvers are often inapplicable for this task due to the excessive demand of computer resources. These difficulties can be overcome in some cases by improving full-wave solvers in order to reduce their computational cost. We have contributed in this respect through investigations of wavelets application for adaptivity in time-domain schemes, and through hybrid schemes allowing for inclusion of efficient models of nonlinear drivers/receivers into existing solvers. Another less recent research project involved radiation prediction for printed circuit boards via Green’s functions approaches.

Wavelets, Fractals, and Applications

The difficult problem of characterization and modeling in the field of EMC requires sometimes advanced or non conventional approaches. These approaches may succeed where conventional methods result inadequate. An example can be the geometrical/statistical description of lightning channel, its radiated fields, and the induced noise on sensitive equipment. It turns out that in this case fractal geometry may provide good modeling approaches. Another example can be the construction of highly-efficient numerical simulation tools for nonuniform interconnects. Wavelets were successfully employed for this task. Representation is often the key to the solution of many problems. This applies to data, signals, functions, operators, equations, etc. The research activities that are outlined in this page required in their development use of non-conventional techniques based on wavelet expansions and fractals for the representation of the unknowns of the problem under investigation.

Testing

Testing is a fundamental aspect of EMC. On one hand, compliance of equipment to regulations must always be assessed by testing. On the other hand, tests and measurements provide the ultimate validation of any modeling approach. Our activities in this field are mostly addressed to theoretical analysis and characterization of testing processes. In particular, we concentrated on cable testing for emission/susceptibility using Bulk Current Injection techniques, and on Reverberation Chambers.

Lightning

Part of the research activities of our group have been focused on lightning. The conduction currents and the electromagnetic fields produced by lightning may cause significant effects on electronic equipment, from interference and malfunctioning to serious damage. Therefore, accurate modeling of lightning channel, currents, and radiated fields is very important for EMC applications. Our contributions are mainly focused on geometrical and electromagnetic modeling of lightning discharge, as well as on coupling mechanisms to susceptible devices.

Education

One of the goals of our group is to promote education in the field of Electromagnetic Compatibility, fields, and circuits. These activities are carried out at different levels, from standard undergraduate and graduate courses at Politecnico di Torino, to seminars, tutorials, and short courses at international conferences and institutions. We have been and are involved in several international projects finalized to EMC education.

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