Design of Anomalous Reflectors by Phase Gradient Unit Cell Based Digitally Coded Metasurface
In this letter, we propose the designs of 1-bit and 2-bit digitally coded metasurfaces, which achieve anomalous reflection-based beam-steering. First, we demonstrate the systematic design flow of coded metasurface using phase gradient digital unit cells to achieve anomalous reflection in the preferred direction for a normally incident plane wave. Initially, the design procedure is analytically implemented to get the phase profiles for 1-bit and 2-bit digitally coded metasurfaces having equal sizes of $10\lambda_0 \times 10\lambda_0$ (where $\lambda_0$ is the free space wavelength at $5.9$ GHz) for a specific reflection angle, $(\theta_r=30^0,\phi_r=0^0)$, and subsequently, the far-field plots are generated. Furthermore, these phase profiles are used to generate 3D-CAD models of the 1-bit and 2-bit metasurfaces using CST, and the desired far-field patterns are obtained having half-power beamwidth (HPBW) of $5^0$. It is observed that the 1-bit coded metasurface produces additional side-lobe levels, which are minimized by use of 2-bit coding. Finally, the proposed 1-bit and 2-bit coded metasurfaces are fabricated, and the anomalously reflected far-field beam is detected by the received power at desired reflection angle and comparing the results with a perfect electric conductor (PEC). The proposed design is suitable for V2X communications and can be scaled to other frequencies.
One of the authors, Debdeep Sarkar, acknowledges the support by Science and Engineering Research Board, Department of Science and Technology (DST), Government of India (GoI) under Grant SRG/2021/000831.
Email Address of Submitting Authormalleboinar@iisc.ac.in
Submitting Author's InstitutionIndian institute of science Bangalore
Submitting Author's Country