  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.
