**1. Introduction**

Recently, the ability to manipulate the electromagnetic (EM) waves has been significantly improved with the help of the emerging concept of metasurface. Driven by the seminal

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

work by Yu et al. [1], metasurfaces have gained considerable attention, and nowadays constitute one of the most promising research thrusts in the field of artificial materials. Della Giovampaola and Engheta presented a method for constructing "metamaterial bytes" through proper spatial mixtures of "digital metamaterial bits" [2] in which the "digital metamaterial bits" are some particles that possess distinct material properties. However, the resulting metamaterial bytes are still described by the effective medium parameters. Cui proposed the general concepts of "coding metamaterial," "digital metamaterial," and "programmable metamaterial," which means that a single metamaterial can be digitally controlled to obtain distinctly different functionalities [3, 4]. Two types of unit cells with 0 and π phase responses to mimic the "0" and "1" elements were proposed for 1-bit digital metamaterial such that they can be controlled using existing digital technology. By designing coding sequences of "0" and "1" elements in coding metamaterials, EM waves can be easily manipulated to obtain different functionalities. And this concept can also be extended to 2-bit (0, π/2, π, and 3π/2) and 3-bit (0, π/8, π/4, 3π/8, π/2, 5π/8, 3π/4, and 7π/8) or more. We will start this chapter by designing a 1-bit coding metasurfaces, which are useful to achieve radar cross-section (RCS) reduction, polarization conversion, anomalous reflection, and vortex beam reflection. By investigating the scattering characteristic of the coding metasurface, we replace the stirrer of a reverberation chamber (RC) with a diffusion coding metasurface in order to improve the field uniformity of the RC, in the meanwhile, increasing the test area of the RC, making the application of the metasurfaces extended to the electromagnetic compatibility (EMC) area.
