Folding Coding Electromagnetic Metasurface for Specular Scattering Shrink and Scattering Pattern Modulation

Electromagnetic coding metasurface became a research hotspot with its modulation capability brought by coding sequence in recent years. A folding form of reflective type coding electromagnetic metasurface is proposed, designed and investigated for its impact on scattering field in reflective hemispherical space. A phase modulation design formula for folding electromagnetic metasurface is established. Folding metasurface is formed by folding a planar 2bit component coding metasurface, which is found to have specular scattering shrink enhancement effect comparing to the corresponding planar form, and generate more scattering beam number for possible wireless communication channel. The scattering shrink volume is improved from -10dB to -15dB in a natural wide frequency band, and -10dB shrink bandwidth is broadened by 3 times reaching covering 8.5-16GHz interval. The scattering beam number is improved from less than 10 to 30 plus for much larger communication capacity. The similarity between folding metasurface and stochastic coarse surface provides possibility for environment blend applications. The folding form provides easy approach for deployment and preservation, which has application potential in low frequency antenna which has a large size.