Wideband GeTe-based near-perfect THz metamaterial absorber for 6G applications

Abstract

Germanium Telluride (GeTe) metamaterial absorber of its first kind is comprehensively studied and demonstrated. The proposed design features a multilayered configuration comprising a geometrically optimized, symmetrical GeTe-driven square split-ring resonator (SSRR) with an auxetic structure in the center and a metallic gold (Au) ground plane, separated by an MF₂ (M = Mg, Ca, Sr, Ba) dielectric substrate. Under normal incidence, the structure exhibits excellent absorption performance at THz waves, maintaining an absorption efficiency above 90 % over a wide frequency ranging from 2.26 THz to 7.32 THz, corresponding to a relative absorption bandwidth (RAB) of 105.6 %. Two prominent absorbing crests are observed at 2.72 THz as well as 6.49 THz, with a central frequency of 4.79 THz. The findings confirm that strategic structural design and optimization play a pivotal role in enhancing the absorber’s performance. Furthermore, by tuning the conductivity of GeTe, the absorber demonstrates dynamically adjustable absorption capabilities, which offer versatile and tunable functionality. In addition, the structure retains stable absorption characteristics across various polarization states and angles which are incidental for both transverse electric (TE) and transverse magnetic (TM) modes, confirming its polarization insensitivity and angular stability. With its wideband response, tunability, and robust absorption behavior, the proposed GeTe-based absorber opens a new dimension for a wide range of THz applications, including 6G communications.