Realization of broadband seismic cloak with uniform polar-metamaterial structures

¹ School of Mathematics and Physics, China University of Geosciences - Wuhan 430074, China
² Dornsife College of Letters, Arts and Sciences, University of Southern California - Los Angeles, CA 90089, USA
³ School of aerospace engineering, Huazhong University of Science and Technology - Wuhan 430074, China

Received: 19 January 2026
Accepted: 7 April 2026

Abstract

Cloaking based on the coordinate transformation theory presents an alternative avenue for developing an earthquake protection method by precisely controlling seismic waves, distinct from the conventional band structure engineering method that attenuates seismic waves within band gaps. Seismic cloaks have remained elusive due to the lack of formal invariance in the Navier equations underlying the operation of the cloak. This challenge is primarily attributed to the elastic tensor breaking the minor symmetry and requiring polar and chiral characteristics that no known materials exhibit. Here, we propose physically realizable seismic cloaks based on a discrete transformation elasticity theory by designing uniform lattice-based polar metamaterials capable of exhibiting polar and chiral elastic tensors. Numerical simulations demonstrate excellent cloaking performance under different types of seismic wave loads including Rayleigh waves, longitudinal (P) waves and transverse (S) waves, and confirm the validity of the proposed cloaks over a wide frequency band.