Near-zero-index-featured Multi-band Highly Directional Radiator with Large Purcell Factors

TLDR: In this article , a near-zero-index-featured resonator based on optical conformal mapping is proposed to achieve highly directional radiation by using dielectrics with refractive index n ≥ 1.

Abstract: Near-zero-index medium could be used to produce perfect planar wave beams, allowing for the design of compact antennas, but implementation is difficult due to the bandwidth and loss limitations. This work proposes a new method for achieving highly directional radiation by introducing a near-zero-index-featured resonator based on optical conformal mapping. The conceptual device performs the same functions as resonators filled with near-zero-index media but can be realized using dielectrics with refractive index n ≥ 1. Multi-band highly directional radiation with large Purcell factor is numerically demonstrated by the proposed high-Q resonator, which may pave the way for efficient production of high gain directive antennas in radar systems.