A Low-Profile Base-Station Antenna

In this paper, a low-profile, high-isolation, dual-polarized antenna using metasurface is proposed for use in the base stations of mobile communications. The antenna consists of two linear-polarized dipoles, which are arranged for horizontal and vertical polarizations. The dipole radiators are fed by two orthogonal printed baluns for the high isolation between the two ports. The metasurface, which is a square patch array periodically printed on a thin low-cost substrate, is inserted between the orthogonal dipoles and the reflector to achieve a low-profile and a bandwidth enhancement. The final prototype with an overall size of 160 mm × 160 mm × 15.2 mm (0.96λo × 0.96λo × 0.09λo at 1.8 GHz) yields a voltage standing wave ratio < 2 bandwidth of > 29% for the two ports and an isolation of > 30 dB. In addition, at both ports, the antenna achieves a gain of > 8.5 dBi and a radiation efficiency of > 83% across the operational bandwidth.