Easily extendable frequency tunable superwideband MIMO antenna for terahertz applications
摘要
An ultrathin tunable antenna element and its multiport configurations for superwideband multiple input multiple output applications are proposed in this paper. The antenna element geometry includes an annular ring-shaped monopole radiator, two ear-shaped ellipses, and a defected partial ground plane. A graphene sheet is placed at the antenna's back side to improve the lower frequency and to achieve tunability. It has an overall volume of 25 × 25 × 1.6 μm3 while operating over a frequency spectrum of 2.3–> 80 THz with a peak realized gain of ~ 12.5 dB with stable radiation patterns. Two-port MIMO configurations (spatial diversity and pattern diversity) with overall volume of 25 × 56.25 × 1.6 μm3 while operating from 0.9 THz to > 80 THz and 2.02 THz to > 80 THz respectively are also analyzed. In addition to this, the extended versions of the spatial diversity configuration to four and six element spatial diversity MIMO configurations with dimensions of 25 × 118.75 μm2 and 25 × 181.25 μm2 respectively are also analyzed. All MIMO configurations exhibit isolation > 15 dB at maximum frequencies, ECC < 0.035, CCL < 0.4b/s/Hz, MEG ~ − 3 dB and TARC < − 10 dB without utilizing any isolation technique. Due to their super wide operational bandwidth, these antenna topologies are ideal for a wide range of applications, such as Industry 4.0, 6G, and ultrathin devices/systems.