Efficient radiational outcoupling of electromagnetic energy from hyperbolic metamaterial resonators

TL;DR

This paper introduces a novel hyperbolic metamaterial-based antenna design that achieves efficient broadband radiational outcoupling, significantly improving gain and enabling multiband or broadband applications.

Contribution

It proposes a compact antenna architecture using hyperbolic metamaterials with patterned layers, enabling efficient energy harvesting and routing across broad frequencies.

Findings

Two-order of magnitude gain improvement predicted

Efficient broadband energy harvesting demonstrated

Frequency routing achieved within subwavelength structures

Abstract

Hyperbolic metamaterials were initially proposed in optics to boost radiation efficiencies of quantum emitters. Adopting this concept for antenna design can allow approaching long-standing challenges in radio physics. For example, impedance matching and gain are among the most challenging antenna parameters to achieve in case when a broadband operation is needed. Here we pro-pose and numerically analyse a new compact antenna design, based on hyperbolic metamaterial slab with a patterned layer on top. Energy from a subwavelength loop antenna is shown to be efficiently harvested into bulk modes of the metamaterial over a broad frequency range. Highly localized propagating waves within the medium have a well-resolved spatial-temporal separation owing to the hyperbolic type of effective permeability tensor. This strong interplay between chromatic and modal dispersions enables routing different frequencies into different spatial locations within compact subwavelength geometry. An array of non-overlapping resonant elements is placed on the metamaterial layer and provides a superior matching of localized electromagnetic energy to the free space radiation. As the result, two-order of magnitude improvement in linear gain of the device is predicted. The proposed new architecture can find a use in applications, where multiband or broadband compact devices are required.