Millimeter Wave Absorber for Secure Identification

TL;DR

This paper presents a thin, flexible metamaterial film that strongly absorbs millimeter-wave radiation at a specific frequency, enabling secure object identification via terahertz imaging.

Contribution

Introduction of a novel, polarization- and angle-insensitive millimeter-wave absorber for secure marking and barcode applications.

Findings

The metamaterial film achieves narrowband absorption near 1 mm wavelength.

The pattern is visually indistinguishable but detectable by terahertz imaging.

The absorber enables secure, non-intrusive object identification.

Abstract

We demonstrate thin, flexible, metamaterial films with a strong, narrowband, polarization- and angle-insensitive absorption designed for wavelengths near one millimeter. These structures, fabricated by photolithography on a commercially available, copper-backed polyimide substrate, are nearly indistinguishable to the unaided human eye but can be easily observed by imaging at the resonance frequency of the film. We demonstrate that these patterns can be used to mark or barcode objects for secure identification with a terahertz imaging system.