Sub-1 GHz and sub-6 GHz reconfigurable MIMO antenna with 28 GHz array on shared chassis for user equipment’s (UEs)

This paper presents the design of a co-located sub-1 GHz long-term evolution (LTE) and sub-6 GHz 5G band antennas implemented in multiple-input-multiple-output (MIMO) configuration. In addition, it demonstrates the integration of the millimetrewave (mm-wave) 5G band antenna arrays. Using the characteristic mode analysis (CMA), these antenna elements have been designed for the user equipment's (UEs) where they share the common ground plane of 150 mm × 70 mm size. Using the varactor and PIN diodes, band switching and frequency agility of the MIMO elements have been achieved to cover the 0.69–1.19 GHz, 2.29–3.29 GHz, 3.93–4.6 GHz, and 5.52–6.45 GHz bands with the S₁₁ = −6.0 dB criterion. At each side of the structure, two 1 × 8 elements patch array antennas with the individual element fractional bandwidth (FBW) of 20.56% to cover 24.0–29.5 GHz band with the beam scanning angle of ±30° have been integrated.