Broadband low-dispersion waveguide-integrated spoof surface plasmon polariton delay lines

Area of Science:

• Electromagnetics and Wave Propagation
• Metamaterials and Plasmonics
• Microwave Engineering

Background:

• Spoof surface plasmon polariton (SSPP) transmission lines exhibit inherent frequency-dependent group velocity (dispersion).
• This monotonic decrease in group velocity with frequency limits their use in applications requiring constant group delay.
• Existing SSPP structures lack broadband low-dispersion characteristics.

Purpose of the Study:

• To propose and validate a novel waveguide-integrated SSPP (WISSPP) structure.
• To achieve broadband low-dispersion characteristics through intrinsic dispersion engineering.
• To enable customizable center frequency and unit-length delay time for integrated microwave systems.

Main Methods:

• Design of a WISSPP structure utilizing intrinsic dispersion engineering.
• Analysis of the transition from anomalous to normal dispersion.
• Experimental validation of the U-shaped group delay profile and dispersion characteristics.

Main Results:

• The WISSPP structure exhibits broadband low-dispersion characteristics.
• A U-shaped group delay profile with near-zero group delay dispersion at the design frequency was achieved.
• Experimental results showed group delay variations within 7% across the 8-12 GHz band.

Conclusions:

• The proposed WISSPP structure effectively overcomes the dispersion limitations of conventional SSPP lines.
• The structure offers miniaturization advantages and tunable parameters for integrated microwave applications.
• This advancement expands the applicability of SSPP technology in high-frequency systems demanding precise delay control.