A 2-D Wideband and Wide Beam-Steering Phased Array Antenna With a Combined Superstrate for 5G Sub-6 GHz Applications

The purpose of this brief is to present a two-dimensional wideband and wide beam-steering phased array antenna with a combined superstrate. The arched metal columns are incorporated in the dipole array antenna to suppress the mutual coupling, resulting in wideband matching and wide beamwidth characteristics in the <inline-formula> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula>-plane. A combined superstrate, comprising metasurface slabs and a dielectric layer, is located above the antenna to increase the beamwidth and enhance the impedance matching property. The same effect can be achieved by optimizing the curvature of the exponential curves of the dipole edge to obtain a deformed dipole. To showcase the wideband wide-scanning capability of the device, a prototype is designed with a scanning range of ±60° in both the <inline-formula> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula>- and <inline-formula> <tex-math notation="LaTeX">${H}$ </tex-math></inline-formula>- plane at 2.5-4.75 GHz (62.1%, active VSWR<inline-formula> <tex-math notation="LaTeX">$\leq 2$ </tex-math></inline-formula>). The simulated co-polarization gain of the array is close to the ideal aperture, which decreases no more than 3 dB in large-angle scanning. To ascertain the viability of the proposed design, an <inline-formula> <tex-math notation="LaTeX">$8\times 8$ </tex-math></inline-formula> prototype is manufactured and subjected to testing. The overall dimension is <inline-formula> <tex-math notation="LaTeX">$2.23\lambda _{0}\times 2.23\lambda _{0}\times 0.24\lambda _{0}\,\,(\lambda _{0}$ </tex-math></inline-formula> is the free space wavelength at 2.5 GHz). Based on the findings of the experiment, there is a good concurrence between the design and measurement outcomes. The proposed array demonstrates the advantages of low-cost, broadband, and wide beam-steering capability, which is expected to be suitable for the implementation of fifth-generation (5G) communication systems.