Wideband FR3 MIMO Antenna Array for NextG Wireless Links

This paper presents a wideband, planar, dual-polarized 4×4 antenna array designed for Frequency-Range 3 band (FR3) operation in future sixth-generation (6G) systems. The wideband (7–24 GHz) capabilities of the array are demonstrated stand-alone and through integration with beamforming ICs (BFICs), enabling multi-beam 4×4 MIMO operation. The compact 5.24 mm lattice (0.42λ at 24 GHz) supports wide-angle scanning and high cross-polarization discrimination, while the architecture is scalable to larger apertures and compatible with next-generation wideband ICs. Over-the-air (OTA) characterization demonstrates the realized gain, radiation patterns, and measured error vector magnitude (EVM), validating beamforming performance across a representative FR3 sub-band. Antenna array fabrication in a commercial PCB process and wafer-level chip-scale packaging (WLCSP) approach for interfacing with BFICs validates the feasibility of combining wideband antenna arrays with BFICs for high-capacity MIMO and phased-array deployments, providing a commercially viable path toward large-scale MIMO systems in 6G and satcom networks.