Low-profile broadband dual-polarized antenna utilizing metasurface

A dual linearly polarized antenna with a low profile and significantly enhanced operating bandwidth is proposed. The primary radiating elements are two conventional loop dipoles fed orthogonally by two printed baluns with wideband and high isolation characteristics. The operating bandwidth is further improved by utilizing a metasurface inserted between the radiators and a shallow cavity reflector. This does not only lower the structure profile but also considerably improves the antenna gain. The final prototype with an overall size of 150mm x 150mm x 15mm (0.83 x 0.83 x 0.083 at the lowest operating frequency of 1.66GHz) has been realized and experimentally validated. The measurements resulted in a -10-dB impedance bandwidth covering a frequency range from 1.66GHz to 2.80GHz (51.1%) for both ports with an isolation of higher than 30dB across the entire band. In addition, at both ports, the antenna achieves a gain of greater than 8.7 dBi and a radiation efficiency greater than 80% across the operating bandwidth.