11.12. INTRODUCTION

Why compatibility in electromagnetics? The general answer is that electronic equipment has to operate in very different types of environments with which it has to remain compatible.

First, equipment does not have to be susceptible to the surrounding electromagnetic (EM) fields generated by the environment. The environment may be external to the entire system, as is the case with natural threats like lightning or electrostatic discharges, or human threats. Some are unintentional, but some systems, mainly military, are also concerned with intentional threats generated by EM weapons. The threat may also be internal to the system itself, generated by other pieces of equipment.

Second, a piece of equipment does not have to generate EM perturbation likely to interfere with another piece of equipment. This is why compatibility with its environment is required.

In aeronautics and aerospace, electromagnetic compatibility (EMC) has been known for a long time. The reason is that all the possible EMC problems are closely connected to reliability and safety. Indeed, in the air or in space, a failure of equipment may lead to serious casualties for the system's functions and, more serious, for people. Eventually, the entire transport domain has become concerned with EMC because of the increase of electronics in all its systems. Since the advent of EM weapons in the 1970s, military systems have also been involved in EMC, with the objective of being totally hardened to EM interference. EMC...