Harnessing superdirectivity in dielectric spherical multilayer antennas

Small form-factor, narrow band, 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.

Automated summary

In a variety of applications, small form-factor, narrow band, and highly directive antennas play a critical role. The study demonstrates that the classical directivity limit can be significantly surpassed for electrically small multilayer spherical antennas even if using purely dielectric materials. Feasible designs of superdirective antennas are established through a stochastic optimization algorithm combined with a rigorous analytic solution.