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Fundamental/harmonics beam control using 1-bit space time-modulated plasma DMA

2023; Springer Science+Business Media; Volume: 55; Issue: 2 Linguagem: Inglês

10.1007/s11082-022-04431-y

1572-817X

Hend A. Malhat, Anas S. Zainud-Deen, Mona M. Badawy,

Antenna Design and Analysis

Abstract This paper investigates a space-time modulated digital metamaterial array (DMA) based on reconfigurable plasma ionization. The DMA consists of 8 × 8 unit-cell elements with total dimensions of 120 × 120 × 3.2 mm 3 . Each unit-cell consists of a ring container filled with argon gas and is backed with a grounded dielectric substrate. The argon gas is ionized into a plasma state through metallic electrodes. The logic state of the unit cell is controlled via the changing of the plasma frequency, $${\omega }_{p}.$$ ω p . The value of $${\omega }_{p}=6\times {10}^{11}\mathrm{ rad}/\mathrm{sec}$$ ω p = 6 × 10 11 rad / sec represents logic “0”, and $${\omega }_{p}=8\times {10}^{11} \mathrm{rad}/\mathrm{sec}$$ ω p = 8 × 10 11 rad / sec represents logic “bit 1”. The periodic time switching of the plasma ionization controls the radiation at the fundamental and harmonic frequencies. The on-time instants and on-time durations control the number of radiated beams, their directions, amplitudes, and side-lobe levels. Different time-switching sequences are investigated for beam steering, dual-sum beams, broadside beams, end-fire beams, multi-beams, and fan-shaped beams for wireless communications applications. The DMA was investigated under different switching sequences for phase-modulation and amplitude-modulation schemes. A full-wave simulation CST Microwave Studio simulator is used to analyze the proposed DMA and the results are compared with ideal point sources array excited with the same switching sequences.