A pattern reconfigurable hybrid graphene-metal terahertz MIMO antenna with improved isolation by metasurface absorber for 6G communication

Abstract

Abstract This paper introduces an innovative 2 × 2 MIMO, Multi-Input Multi-Output, antenna working in the sub-Terahertz (THz) band for 6G, 6-Generation, communications (0.1–1.2 THz). This antenna was designed with main metal octagonal patches and parasitic graphene elements, providing pattern reconfigurable antenna for Single-Input Single-Output (SISO) and MIMO applications. In the YZ-plane, aforementioned antenna illustrates a tunable pattern (0°, +70°, −70°) for SISO in three distinct states. In the XZ-plane, it obtains a versatile MIMO function with a controllable pattern (0°, ±20°, ±45°, ±75°) across four states, simultaneously. The adaptability of the radiation pattern is originated from changing graphene conductivity through biasing. In addition, a graphene metasurface was applied as an absorber, moderately improving isolation between 2 antenna elements, minimizing interference, and enhancing the overall system capability. The proposed schematization achieves a significant isolation up to −35 dB within the MIMO antenna’s operational frequency band. Moreover, the MIMO antenna touches a maximum gain of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>9.5</mml:mn> <mml:mi mathvariant="italic"> dBi</mml:mi> <mml:mo>,</mml:mo> <mml:mspace width="0.25em"/> </mml:math> maximum impedance bandwidth of approximately 91% during different states, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>10</mml:mn> <mml:mi mathvariant="italic"> dBi</mml:mi> </mml:math> Diversity Gain, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>2.6</mml:mn> <mml:mn>2</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>7</mml:mn> </mml:mrow> </mml:msup> </mml:math> ECC in the resonance frequency, which demonstrates novelty designing, remarkable pros, and broad applications in the landscape evolution of 6G communication networks.