Multifunction plasma genus holographic antenna for near/far-field focusing using a single structure

This paper introduces a plasma-based genus holographic reflectarray antenna (GHRA) for reconfigurable electromagnetic wave manipulation at 10 GHz. It introduces unprecedented dual-mode near-field (NF) focusing and far-field radiation within a compact 31.5 × 31.5 cm2 planar surface. By leveraging plasma frequency modulation, the GHRA dynamically tunes surface impedance from 267 Ω to 579 Ω, enabling precise electronic beam steering from θ = − 40° to + 40° with a peak gain of 28.7 dBi at broadside and 17.4 dBi at extreme angles. A novel chessboard arrangement facilitates dual-beam radiation from a single activated surface, producing beams at (θ₁ = 10°, φ₁ = 0°) and (θ₂ = − 30°, φ₂ = 0°) with gains of 21.2 dBi and 20.6 dBi, respectively. For both activated surfaces, dual beams with different directions are radiated. Beam1 at (θ1 = 10°, θ2 = − 30°, φ1 = 0° with peak gain of 18.7 dBi and Beam2 at (θ3 = 10°, θ4 = − 30°, φ1 = 0°) with peak gain of 18.7 dBi. The GHRA’s dual-surface design supports simultaneous NF focusing at Ro = 63.6 cm, yielding a tightly focused spot (3.25 cm × 3.75 cm) with a side-lobe level of -17.4 dB, and bidirectional far-field radiation with a 24.7 dBi gain. This innovative plasma-based technology, validated through simulations, offers unparalleled flexibility for applications in medical therapy, satellite communications, and phased-array radar, redefining the boundaries of antenna performance and adaptability.