Metamaterials are composed of periodic or quasi‐periodic subwavelength structures, having electric and/or magnetic responses. Metamaterials can arbitrarily tailor the refractive index by artificially tailoring the unit‐cell geometries and dimensions. Recent years, as the two dimensional equivalent of bulk metamaterials, metasurfaces have caused considerable attentions due to the lower profile and simpler to fabricate than bulk metamaterials. Metasurfaces can impart discontinuities on electromagnetic wavefronts and can achieve the arbitrary transmission phase of the whole period range. Metamaterials and metasurfaces have led to the realizations of novel electromagnetic properties and functionalities through tailoring subwavelength structures and integrating functional materials. In this letter, two planar lenses are respectively proposed to control the beam direction of the horn antenna by using a gradient refractive index (GRIN) metamaterial and a gradient phase (GRPH) metasurface. It is shown that the antenna beam direction can be steered by controlling the refractive index of the GRIN metamaterial or the transmission phase of the GRPH metasurface. The differences between the two planar lenses for controlling the antenna beam are illustrated.

A novel wideband dual-polarized antenna with load of a disk is presented in this letter. The antenna is composed of two cross magneto-electric dipole antennas vertically fixed on an aluminum plate as ground plane, which are excited by two similar Γ-shaped coaxial feeder. Furthermore, in order to further broaden the impedance bandwidth, a disc-shaped resonator is loaded on the front end of the dipole. And a metal barrel reflector is loaded around the antenna to further improve the antenna's radiation characteristics. Measured results show that the proposed antenna achieves a 10 dB with bandwidth of 1.2-2.4 GHz, and its port isolation is higher than 28 dB. Moreover, stable radiation pattern with a peak gain of 7.7-9.2 dB is obtained within that band.

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