Wire-Medium Hyperlens for Enhancing Radiation From Subwavelength Dipole Sources

Hyperlens is a metamaterial structure initially proposed for magnifying imaging of subwavelength scattering objects. Here, we show that a wire-medium (WM) hyperlens can be used also for significant enhancement of radiation from small sources to free space and that this enhancement holds in the ultra-wide frequency band. We investigate how the divergence of metal wires modifies the radiated power of a dipole, comparing with an array of parallel wires, and investigate the impact of other design parameters. Next, we implement the optimized hyperlens in the microwave range and verify the theoretical results experimentally. We believe that this work will help to introduce and develop hyperlenses for a number of applications where broadband radiation enhancement of subwavelength sources is needed.