The 90° Rotating Eaton Lens Synthesized by Metasurfaces

In this letter, the two-dimensional 90° rotating Eaton lens is designed and realized by flat metasurfaces. Two kinds of unit-cell metallization are employed, namely the square patch and the mushroom structure, the latter adopted to achieve the higher values of equivalent refractive indices required by the regions near the center of the circular lens. Designs by computer simulations have demonstrated the successful bending of impingent waves by right angles, via field distributions over the metasurface as well as by simulated gains towards the rotated direction. A prototype of the design was also manufactured, the measured surface field distribution and far-field radiation gain patterns of which corroborate the theoretical prediction of the lens' ability to rotate waves by 90°.