Wide-Band Circularly Polarized ReflectarrayUsing Graphene-Based Pancharatnam-Berry Phase Unit-Cells for Terahertz...

Area of Science:

• Electromagnetics and Optics
• Materials Science
• Nanotechnology

Background:

• Terahertz (THz) technology requires efficient components for communication.
• Graphene's unique properties offer potential for novel THz devices.
• Existing graphene-based devices often suffer from narrow bandwidth and limited phase tunability.

Purpose of the Study:

• To propose and theoretically investigate a wide-band, high-gain circularly polarized (CP) graphene-based reflectarray for THz applications.
• To overcome the narrow-band limitations of traditional graphene devices.
• To demonstrate a novel design principle for high-performance CP reflectarrays in the THz regime.

Main Methods:

• Utilizing the Pancharatnam-Berry (PB) phase principle for tunable phase control.
• Designing graphene-based unit-cells capable of a 360° phase range through rotation.
• Developing a wide-band focusing metasurface and a CP reflectarray based on the proposed unit-cells.
• Conducting numerical simulations to evaluate performance metrics.

Main Results:

• The proposed graphene-based unit-cell achieves a tunable phase range of 360° over a wide band (1.4–1.7 THz).
• Simulations show the reflectarray achieves a stable high gain up to 15 dBic.
• An axial ratio of approximately 2.1 dB is maintained across the 1.4–1.7 THz band.

Conclusions:

• The designed graphene-based reflectarray demonstrates superior bandwidth and phase tunability compared to previous designs.
• The device exhibits excellent radiation performance, suitable for THz communication systems.
• The design offers a new pathway for creating high-performance CP reflectarrays in the THz frequency range.