Tunable leaky-wave radiation by graphene-covered corrugated surfaces

Area of Science:

• Terahertz (THz) technology
• Plasmonics
• Antenna engineering

Background:

• Spoof surface plasmon polaritons (SSPPs) offer unique waveguiding properties at lower frequencies.
• Graphene's tunable electronic properties make it a promising material for dynamic control of electromagnetic waves.
• Leaky-wave antennas (LWAs) are known for their wide scanning capabilities.

Purpose of the Study:

• To propose and analyze a novel graphene-covered subwavelength metallic grating as a leaky-wave antenna.
• To demonstrate the conversion of spoof surface plasmon guided waves to free-space radiation at THz frequencies.
• To achieve electronic beam scanning with controlled gain and sidelobe levels.

Main Methods:

• Utilizing a sinusoidally modulated surface impedance concept for antenna design.
• Employing an analytical circuit model to derive the surface impedance.
• Realizing tunable surface impedance by modulating graphene conductivity via bias voltage.
• Incorporating a mode-converting section to enhance return loss.

Main Results:

• The proposed antenna demonstrates efficient conversion of SSPPs to radiated power.
• Electronic beam scanning is achieved by tuning the graphene Fermi level.
• The antenna exhibits an almost constant gain and low sidelobe levels across the scanning range.
• The integrated mode-converting section significantly improves the antenna's return loss.

Conclusions:

• The graphene-covered metallic grating is a viable platform for THz leaky-wave antennas.
• Tunability of graphene enables dynamic control over antenna radiation patterns.
• The proposed design offers a promising solution for steerable THz antennas with improved performance.