6. Conclusion

This article begins with an introduction to civil and military industrial applications, followed by a discussion of the specificities of the millimeter-wave spectrum, namely high attenuation in free space, and antenna efficiency issues due to the metallic and dielectric losses induced by the materials used, particularly in the design of printed-technology antenna arrays. These approaches require a thorough understanding of the electrical characteristics of these materials, in order to predict the overall losses and therefore the antenna efficiencies envisaged. While millimeter waves have the great advantage of enabling high-speed data transmission, or providing unrivalled resolution for radar systems, the difficulty of implementing directional and reconfigurable antenna systems remains a key issue, and one which will prompt a number of studies in the years to come:

...