Superdirective Mixed-Multipole-based Unidirectional Spherical Dielectric Lens Antennas

TL;DR

This paper presents a new design for superdirective unidirectional spherical dielectric lens antennas using multilayered high-permittivity spheres and mixed-multipole excitation, optimized via genetic algorithms for enhanced directivity.

Contribution

It introduces a novel multilayered sphere design with mixed-multipole excitation and GA optimization to achieve superdirective unidirectional dielectric lens antennas.

Findings

Achieved high directivity and front-to-back ratio in simulations.

Validated superdirective performance against known bounds.

Demonstrated potential for experimental realization.

Abstract

Studies of superdirective dielectric lens antennas are reported emphasizing unidirectional properties. The developed antennas are based on the higher-order transverse electric and magnetic modes present in a multilayered sphere realized with high permittivity dielectrics. The superdirective properties of the lenses are empowered by exciting them with a basic unidirectional mixed-multipole antenna. Genetic algorithm (GA) optimization was employed to identify configurations that yielded both large directivity and front-to-back ratio outcomes. The analytical evaluations of several example systems of spheres having different outer radii and numbers of layers are described. Their radiated field patterns are presented along with comparisons with known directivity bounds to confirm their superdirective performance characteristics. Subsequent numerical assessments with commercial full-wave finite element simulations of more realistic versions of several selected examples illustrate their potential for experimental realization.