Wire Resonator as a Broadband Huygens Superscatterer

TL;DR

This paper introduces a broadband Huygens superscatterer using a circular array of metal wires, enabling directional electromagnetic scattering over a wide frequency range with high-order magnetic multipoles, suitable for advanced wave control devices.

Contribution

The paper presents a novel broadband resonant Huygens element based on wire arrays, expanding the bandwidth and magnetic multipole complexity compared to traditional narrowband designs.

Findings

Achieves over 10% bandwidth of the carrier frequency.

Demonstrates high-order magnetic multipoles with quality factors near 6,000.

Experimental validation at GHz frequencies.

Abstract

Interference phenomena render tailoring propagation of electromagnetic waves by controlling phases of several scattering channels. Huygens element, being a representative example of this approach, allows enhancement of the scattering from an object in a forward direction, while the reflection is suppressed. However, a typical resonant realization of Huygens element employs constructive interference between electric and magnetic dipolar resonances that makes it relatively narrowband. Here we develop the concept of a broadband resonant Huygens element, based on a circular array of vertically aligned metal wires. Accurate management of multipole interference in an electrically small structure results in directional scattering over a large bandwidth, acceding 10% of the carrier frequency. Being constructed from non-magnetic materials, this structure demonstrates a strong magnetic response appearing in dominating magnetic multipoles over electric counterparts. Moreover, we predict and observe very high-order magnetic hexadecapole (M16-pole) and magnetic triakontadipole (M32-pole) with quality factors, approaching 6,000. The experimental demonstration is performed at the low GHz spectral range. Our findings shed light on a simple approach for engineering compact and open electromagnetic devices (antennas, directional reflectors, refractors, etc.) able to tailor wave propagation in a broadband domain, concentrate strong magnetic field, and generate high-order magnetic multipoles.