Dual-band high-gain microstrip antenna with a reflective focusing metasurface for linear and circular polarizations

This paper proposes a dual-band high-gain microstrip antenna with a reflective metasurface (MS). The initial designed coaxial-fed laminated microstrip antenna can realize linear polarization (LP) radiation at the lower frequency of 5 GHz and circular polarization (CP) radiation at the higher frequency of 11 GHz, with a relatively low gain of about 5.8 dBi and 5.4 dBic, respectively. To enhance the radiation performance of the microstrip antenna, a reflective focusing MS is proposed, which can focus LP and CP waves at 5 GHz and 11 GHz, respectively. The MS antenna system is constructed by placing the initially designed microstrip antenna on the focal point of the reflective focusing MS, which can achieve the high-gain performance of 13.4 dBi for the LP radiation at 5 GHz, and 18 dBic for the CP radiation at 11 GHz, respectively. The proposed MS and feed antenna were designed and fabricated, and the experimental data were consistent with the simulation results, which verifies the feasibility of the proposed scheme. The proposed reflective focusing MS antenna could provide potential application in the modern wireless communication system.