Focused Beam Direction Adjustment By Metasurface: Theoretical Analysis and Experimental Verification

In this paper, a phase expression is derived to calculate the compensation phase of each point on the metasurface (MS), which is then used to generate a focused beam with different elevation (θ) and azimuth (φ) angles. The simulation results show that the expression can achieve both 1D and 2D focused beam scanning. An MS with an expected beam direction of θ and φ both equal to 45∘ is fabricated using the derived phase expression and a designed phase control unit. The final measurement results indicate that the beam can be generated with minimal error in the desired direction. Furthermore, due to the focusing effect of the MS, more power is concentrated in the direction of beam propagation. When compared with the system without the MS, the harvested power by the receiver can be improved by at least 39.0% (η>39.0%) across all measured ranges, with a peak value of η reaching 53.0% when the system incorporates the proposed MS. This means that the designed MS can adjust the direction of the generated beam while concentrating power on the beam propagation path. The method proposed in this paper can be applied to the moving target power transmission application.