## PROJECT SUMMARY

The fields inside enclosed environment, i.e. fuselage and/or cockpit, either caused by equipment (unwanted emission) or wanted emissions due to mobile communication equipment, or fields penetrating such an enclosed environment (due to leakage or through windows) will resonate.

This activity assumes a stochastic behavior of the fields in and around such enclosed environments. With respect to EMC, the main focus is on the risk of EMI in the tail of a probability function, which means in theory that many simulations have to be performed.

A part of the work is dedicated to the resonances inside a (semi) enclosed environment resulting in a higher field strength than originally estimated. As a result, there is a higher risk of interference. The Quality factor describes this resonance as a lumped parameter. The question is: is this lumped parameter sufficient to quantify the risk of interference.

Another part of the work is coupling of resonating electromagnetic fields into cables. In practical systems there is a statistical spread in many parameters e.g. in position of wires, size of small apertures, material properties etc. Exploring the parameters space to establish the statistics of the response by repeated computation is very time consuming requiring thousands of computations. Alternative approaches where only a small number of computations is required to obtain statistics will be explored.

### RESEARCH METHOD

Determine the validity of the central limit theorem, resulting in the chi-squared (Rayleigh) distribution for enclosed environments, in case the environment is not completely resonant or not completely enclosed. Where are the limits in theory, taking actual structures into account, and what is the impact on fields. Also investigate the impact of fields very near to metal structures by varying the boundary conditions.

Investigation on variational parameters to be included in traditional transmission line models. Sensitivity analysis methods, investigation on 'Monte-Carlo' analysis techniques as used in circuit simulations, Importance Sampling as well as other techniques are possible candidates.

### OBJECTIVES

- To find critical parameters, i.e. which parameters have a main influence on the extreme field strengths.
- Full validated and integrated solutions to model, simulate and test air vehicles for EM aspects during the whole life cycle.
- Applicability of HIRF SE will be extended to large air vehicles by using existing data on a large air vehicle.
- To build (from past and ongoing research work) an integrated approach with an open and evolutionary architecture.

## PARTICIPATING TE MEMBERS

- prof.dr.ir.ing. F.B.J. Leferink
- R. Vogt-Ardatjew, MSc.