Coupled Decorated Membrane Resonators with Large Willis Coupling

TL;DR

This paper presents experimental and theoretical analysis of coupled decorated membrane resonators demonstrating large Willis coupling and reflection asymmetry, advancing acoustic metamaterials design.

Contribution

It introduces a novel coupled DMR design with significant Willis coupling, validated by experiments and theoretical analysis based on Greens function formulism.

Findings

Achieved a Willis coupling coefficient of 2.5

Demonstrated near extreme reflection asymmetry

Validated theoretical predictions with experimental results

Abstract

We report the experimental studies on an acoustic scatterer consisting of a pair of coupled decorated membrane resonators (DMRs) that exhibits near extreme contrast in reflection asymmetry and strong Willis coupling coefficient with amplitude of 2.5 and polarizability cross term of 1.1 x 10-8 ms2. The design is based on the theoretical analysis using the Greens function formulism we developed earlier. The clean line shapes of the real and the imaginary parts of the Willis coefficient clear show, even by visual inspection, that the Kramers-Kronig relations are satisfied. Theoretical analysis agrees well with the major features of the experimental results.