9. Conclusion

High-frequency conductors have followed the technical upheaval of the last twenty years. The realization that it was possible to manufacture very powerful microcomputers and high-performance, miniaturized communicating objects for the general public, guided researchers' choices and enabled new, daring projects to flourish. The result has been a deepening of often long-standing concepts, such as two- or three-dimensional periodic structures, air lines, mechanical relays (now micromechanical), the use of Hertzian optics (now quasi-optical), and finally the renewal of the notion of linear conductor by a broader concept of two-dimensional coupling by the electromagnetic field. To use the language of electromagnetic compatibility, we are now studying the "radiated mode" rather than the "conducted mode" (electromagnetic compatibility uses transfer impedance in radiated mode and transfer impedance...