LAUSR

This paper presents the design and the realization of broadband circularly polarized (CP) Fabry–Perot resonant antenna using a single superstrate for the fifth-generation (5G) wireless multiple-input-multiple-output (MIMO) applications. The antenna consists of a corner cut patch with a diagonal slot and a superstrate. The individual resonances of the corner cut patch and patch with diagonal slot are overlapped to improve the intrinsic narrow impedance and axial ratio (AR) bandwidths of the single-fed patch antennas. A half-wavelength spaced superstrate having a half-wavelength thickness is employed as a partially reflecting surface (PRS) for high gain and wide AR as well as impedance bandwidths. The design procedure and mechanisms of the PRS are discussed in detail through the equivalent circuit and ray tracing analysis. Simulated and measured results show that the proposed antennas have a wide operational bandwidth of 25–33 GHz (27.6%) for $\vert \text{S}_{11}\vert < -10$ dB with a stable gain achieving a maximum value of 14.1 dBiC and a wide 3-dB AR bandwidth ranging from 26–31.3 GHz (17%). This operational bandwidth of the antenna covers the proposed entire global 5G millimeter wave (mmWave) spectrum (26–29.5 GHz). Moreover, a $2\times 2$ MIMO antenna is designed using the proposed antenna in such a way that the polarization diversity of the adjacent radiator is exploited, resulting in high isolation between antenna elements and low-envelope correlation coefficient, which makes it a suitable candidate for future 5G MIMO applications.