Design and Analysis of Plasma-Based Reconfigurable Maxwell Fish-Eye-Lens Antennas

This paper investigates the feasibility of using plasma dielectric material to form a reconfigurable Maxwell Fish-Eye (MFE) lens antenna. While MFE lenses have been extensively studied both theoretically and experimentally, designing MFE lenses made of a dielectric with a refractive index less than one represents a new frontier. To this end, existing analytical design equations for MFE lenses need to be modified, and the refractive index distribution profile must be redefined. Therefore, a key novelty of this research is the development of updated analytical design equations for MFE lenses incorporating plasma dielectrics. To this end, the refractive index profile of this lens is theoretically derived based on the hyperbolic function model, employing a stepped index profile to discretize the refractive index along its radius, resulting in a staircase-like profile. The step-by-step procedure for calculating the characteristics of each plasma layer is detailed, starting with the initial refractive index of n0 = 1 at the center of the sphere, which decreases towards the outer layers of the lens. The study includes the design, simulation, and analysis of both spherical and hemispherical MFE plasma lenses, utilizing a rectangular waveguide feed for illuminating the lens. Numerical simulations evaluate the performance of these plasma-based lens antennas, demonstrating promising results in beam focusing and gain enhancement. Energizing the lens excites the plasma to form a reconfigurable structure, resulting in a 12.8 dBi radiation gain enhancement for the hemispherical configuration and 4.9 dBi for the spherical configuration. These features make the novel lens antenna suitable for various applications in space communication. Specifically, the enhanced signal quality and dynamic beam-forming capabilities make it ideal for satellite communication, deep space missions, and interplanetary networks. The ability to dynamically adjust the radiation pattern and beam direction provides significant advantages in improving communication efficiency and reliability in challenging space environments.