High-efficiency polarization conversion based on spatial dispersion modulation of spoof surface plasmon polaritons

Area of Science:

• Electromagnetics
• Metamaterials
• Plasmonics

Background:

• Polarization conversion is crucial for various electromagnetic applications.
• Spoof surface plasmon polaritons (SSPPs) offer unique waveguiding properties at lower frequencies.
• Existing methods for polarization conversion often face limitations in efficiency or bandwidth.

Purpose of the Study:

• To propose and demonstrate a novel high-efficiency polarization conversion technique.
• To utilize spatial dispersion modulation of SSPPs for polarization control.
• To achieve broadband linear-to-circular (LTC) polarization conversion.

Main Methods:

• Designing a fishbone structure to create different wave vector (k) values in transverse directions.
• Introducing an orthogonal phase difference using the larger k of SSPP waves.
• Implementing a gradient k in the z-direction for efficient coupling of incident waves into SSPP modes.
• Rotating the fishbone structure to control the polarization state of transmitted waves.

Main Results:

• A polarization converter prototype operating at 8 GHz was designed, fabricated, and measured.
• Simulations and experiments confirmed high-efficiency linear-to-circular polarization conversion.
• The device achieved broadband operation from 6.9 GHz to 9.6 GHz.

Conclusions:

• The proposed spatial dispersion modulation of SSPPs is an effective method for high-efficiency polarization conversion.
• The demonstrated device offers broadband LTC polarization conversion, suitable for practical applications.
• This work opens new avenues for designing advanced polarization manipulation devices using SSPPs.