Harnessing superdirectivity in dielectric spherical multilayer antennas

TL;DR

This paper demonstrates that dielectric multilayer spherical antennas can significantly surpass classical directivity limits for small, narrowband antennas, using a stochastic optimization approach and analytic solutions.

Contribution

It introduces a novel method to achieve superdirectivity in dielectric spherical antennas, surpassing classical limits with feasible designs.

Findings

Superdirective dielectric spherical antennas are achievable.

Optimization combined with analytic solutions enables design.

Experimental feasibility of superdirective antennas is demonstrated.

Abstract

Small form-factor, narrowband, and highly directive antennas are of critical importance in a variety of applications spanning wireless communications, remote sensing, Raman spectroscopy, and single photon emission enhancement. Surprisingly, we show that the classical directivity limit can be appreciably surpassed for electrically small multilayer spherical antennas excited by a point electric dipole even if limiting ourselves to purely dielectric materials. Experimentally feasible designs of superdirective antennas are established by using a stochastic optimization algorithm combined with a rigorous analytic solution.