A Metasurface-Based Low-Profile Wideband Circularly Polarized Patch Antenna for 5G Millimeter-Wave Systems

This paper presents the design and realization of a metasurface-based low-profile wideband Circularly Polarized (CP) patch antenna with high performance for Fifth-generation (5G) communication systems. The antenna consists of a modified patch, sandwiched between an array of <inline-formula> <tex-math notation="LaTeX">$4\times4$ </tex-math></inline-formula> symmetrical square ring Metasurface (MTS) and a ground plane. Initially, the intrinsic narrow bandwidth of the conventional patch antenna is increased using a diagonal rectangular slot. For further performance enhancement, the additional resonances and CP radiations are achieved for wideband operation in terms of impedance and Axial Ratio (AR) by effective excitation of surface waves propagating along the MTS. The stacking of MTS on the modified patch without any air gap resulted in an overall compact size of <inline-formula> <tex-math notation="LaTeX">$1.1\lambda _{0} \times 1.1\lambda _{0} \times 0.093\lambda _{0}$ </tex-math></inline-formula>. Simulated and measured results show that the MTS-based antenna offers a wide impedance bandwidth ranging from 24 – 34.1 GHz (34.7%) for <inline-formula> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert < -10$ </tex-math></inline-formula> with a maximum gain of 11 dBic and a 3-dB AR bandwidth of 24.1 – 29.5 GHz (20.1 %). Moreover, the proposed antenna has a smooth gain response with a small variation in its gain (9.5 – 11 dBic) and a stable left-hand CP radiation in the desired frequency range. The operating bandwidth of this antenna is covering the proposed entire global millimeter-wave spectrum (24.2 – 29.5 GHz) for 5G communication systems.