An X / Ku - Band Focusing Anisotropic Metasurface for Low Cross - Polarization Lens Antenna Application

Abstract

An X/Ku-band flat lens antenna based on a dual-frequency anisotropic metasurface is proposed in this paper. The function of the anisotropic metasurface is to focus the incident plane waves around 10 GHz and 14 GHz on different spots. Then we place a Vivaldi antenna with its phase centers at 10 GHz and 14 GHz well matching the focal spot of the metasurface at each frequency to build a flat lens antenna. The lens antenna has a peak gain of 18.5 dB and cross-polarization levels of lower than −20 dB at 10 GHz with −1 dB gain bandwidth of 9.8–10.4 GHz, while it has a peak gain of 18.8 dB and cross-polarization levels of lower than −30 dB at 14 GHz with the bandwidth of 13.8–14.2 GHz. Besides single working band, the antenna can simultaneously operate at 10 GHz and 14 GHz with gains of 16.2 dB and 16.5 dB, respectively. Measured results have a good agreement with the simulated ones.