ANISOTROPIC FRACTAL METASURFACE-BASED ANTENNA WITH CONTRARY BEAMS

The capabilities of the dual-band bidirectional dipole antenna to couple near-field with the metasurface have been investigated both numerically and experimentally. By properly positioning the radiating element with respect to the metasurface, the proposed antenna can emit in forward or in the backward direction. It is shown that the array of fractal closed ring resonators formed as the anisotropic metasurface can be excited to generate the opposite angular beams even though the reflection coefficient of the metasurface is high with the same value of 0.8. This is due to the fact that the conversion of evanescent to propagation waves from transmitting closely antenna to the far-zone existed. To our knowledge, this is the first report for a metasurface applied to dualband antenna with contrary beams. This proposed metasurface-based antenna concept may present new opportunities in the design of multi-functional antennas. (C) 2017 Wiley Periodicals, Inc.