Polarization-insensitive graphene-based band-notched frequency selective absorber at terahertz

Area of Science:

• Terahertz (THz) technology
• Metamaterials and electromagnetic devices

Background:

• Frequency selective surfaces (FSS) are crucial for controlling electromagnetic wave propagation.
• Graphene's unique properties enable advanced absorber designs.
• Achieving polarization-insensitive and tunable absorption with reflective notches remains a challenge.

Purpose of the Study:

• To introduce a novel polarization-insensitive graphene-based frequency selective absorber (FSA) for THz applications.
• To design an FSA with two distinct absorption bands and a central reflection notch.
• To demonstrate tunability and stability under oblique incidence.

Main Methods:

• A multi-layered structure comprising a lossy FSS (graphene-based), a bandstop FSS, and a metal backing was designed.
• Wideband absorption was achieved using a graphene lossy layer.
• A reflection notch was introduced by integrating a bandstop FSS.
• Extensive electromagnetic simulations were performed to validate the design.

Main Results:

• The FSA exhibits two absorption bands (>80% absorptivity) from 0.30-0.57 THz and 0.67-0.90 THz.
• A reflection notch is achieved at 0.60 THz.
• The structure is polarization-insensitive and stable up to 40° oblique incidence.
• Absorption characteristics are tunable via graphene's chemical potential.

Conclusions:

• The proposed graphene-based FSA offers a promising solution for THz applications requiring selective absorption and reflection.
• The design simplifies fabrication by avoiding complex 3D structures and welding.
• Tunability and stability make it suitable for diverse THz systems.