Characterising electromagnetic fields of integrated electronic systems in enclosures - a ray-wave approach

Electronic consumer goods and internet-enabled smart infrastructures require highly integrated miniature electronic systems. One of the main problem with this miniaturisation is that unwanted interactions can arise between different components. Depending on the rate of change of currents within electronic components, these components radiate electromagnetic (EM) waves which can couple into other parts of the structure and can cause interferences. Controlling electromagnetic interferences within electronic devices is becoming an increasingly important challenge. Digital clock speeds are relentlessly increasing already exceeding 10 GHz in high-performance systems and expected to reach 20 GHz by 2020. This is within range of highly sensitive radio frequencies where analogue blocks and chip-sized components become efficient radiators and receivers. In addition, increasing circuit density and decreasing voltage supplies will result in decreased immunity levels. Future design processes of integrated electronic systems will therefore have to include a much more detailed electromagnetic compatibility (EMC) characterisation than is done at present. Carrying out EMC studies for complex multi-signal components within a device in a fast and efficient way will simplify design decisions in industry enormously and will help to bring down costs.

The challenges of delivering fast and reliable EMC modelling tools at high frequencies are enormous; determining EM fields in a complex multi-source environment and in the GHz range including multiple-reflections, diffraction and interferences is a hard task already. For realistic electronic devices, the underlying source fields depend in addition on the (a-priori unknown) mode of operation and are thus aperiodic and time dependent; they act in many ways like stochastic, uncorrelated input signals. Indeed, no EMC methodology for modelling transient signals inside and outside of electronic devices originating from decorrelated, noisy sources exists today.

This proposal sets out to meet this challenge head-on by developing an efficient numerical method and accompanying measurement techniques for the modelling of radiated transient EM fields inside and outside of multifunction electronic devices. The new numerical method is based on ideas from wave chaos theory using Wigner-Weyl transformation and phase-space propagation techniques. It makes use of the connections between wave correlation functions and phase space densities. Methods for efficiently propagating these densities have been developed recently by members of the project team. In this way, we can work directly in terms of statistical measures such as averages and field correlation functions appropriate for stochastic fields. This innovative approach demands input data from measurements which require a rethink of standard measurement techniques. In particular, correlated two-probe near-field measurements of electronic components become necessary which will be developed and tested as part of the project.

The proposed way of approaching EMC issues is completely new and becomes possible only due to the unique mix of expertise available at the University of Nottingham both from the Mathematical Sciences and the Electrical Engineering side Support provided by two industrial partners, inuTech and Computer Simulation Technology (CST), will be vital throughout. This fresh way of thinking will provide the necessary leap within EMC research to satisfy the demands of the electronics industry; it will enhance the applicability of existing EMC protocols and provide the tools to meet the challenges of the future.

The impact of this research will be twofold: on the one hand it will change the way research into 'Electromagnetic Compatibility' (EMC) is conducted and will thus have a strong influence on a whole research field and on the academic and industrial practitioners involved; on the other hand, the proposed research will deliver significant commercial benefits, both to the collaborating partners and to wider sectors of industry. The research will provide technology which will lead to reduced product development times and new EMC standards for electromagnetic devices with realistic modes of operation. The outcomes of this project will in the long run thus be of significant benefit to the electronics, communications, automotive, military, aerospace and scientific engineering industries.

The simplified electromagnetic emission models will have many applications in the context of electromagnetic compatibility. They will enable a large range of "what-if'' studies on equipment emissions allowing much more in depth design decisions at the modelling stage thus reducing costly prototype building and testing. The electronics sectors will thus benefit in particular since the need for rapid product development is being driven by pressure from short commercial lifetimes of modern electronic devices. General engineering industries will benefit through the assured EMC compliance of all equipment. There is a variety of beneficial implications beyond EMC which will impact in particular on the military and health sectors. Benefits for the military will be through better understanding and suppression of electromagnetic emission levels thus helping to protect the camouflage of military equipment, the health sector will be able to assess emission levels on patients in more detail.

The impact on reduced product development time may be realised in the near term (1-5 years), since electromagnetic simulations are already utilised in all identified sectors, and they are well positioned and ready to benefit from the research outcomes. In the longer term (5-10 years), further research and development leading on from this research will deliver virtual design and test tools for ever more complex electronic architectures. The methodology has the potential to become a standard tool in industry on this time scale with significant commercial value. To increase the likelihood that these benefits are realised, we have developed this proposal in consultation with our industrial partners inuTech and CST and included a process evaluation and dissemination package within the proposed work program (WP6 in the case for support). A positive outcome from the evaluation of the models will provide industrial partners with tangible proof of capability and benefits, which will encourage them to adopt the technology in their businesses. It will inform new EMC standards which will have a lasting impact on the whole electronics industry as well as associated manufacturing industries (automotive, aerospace etc) - the way electronic components are placed both within integrated electronic devices and in sensitive areas of mechanical structures (cars, areoplaens) will be based and assessed on these guidelines.