At optical frequencies, highly localized surface waves kn own as surface plasmon polaritons (SPPs) Surface Plasmon polaritons, generally arise at the boundary between two materials having contrasting permittivity. To replicate these effects specifically at lower frequencies, researchers here have introduced plasmonic metamaterials. This method emplys subwavelength structural patterns on the metal surfaces in order to create spoof SPPs at microwave or terahertz fre quencies.Due to their inheritance of natural SPPs' dispersion charac teristics, field confinement, and subwavelength resolution, spoof SP Ps are anticipated to providenovel approaches to highly integrated, small, and highly performing advanced circuits and systems.The ev olution of spoof SPPs in recent years is covered in this paper, with particular attention paid to the fundamental idea, theory, design pro cess, and microwave engineering applications.The theory and conc ept of SPPs and spoof SPPs are first presented, An overview of this transition from conventional bulky waveguides to the compact ultrathin transmission lines (TLs) emphasizing the unique benefits offered by this new class of TLs this class of TLs has been reviewed. This research discusses the corresponding design methodology, innovative approaches for achieving reconfigurable spoof SPP structures and appropriate feeding mechanisms for spoof SPP transmission lines. In addition, practical implementations of plasmonic circuits are presented, that enables the researcher to developed SPP-based antennas, passive components and active devices for Applications. Finally, this research will contribute for the potential RF applications and prospective research directions for microwave spoof SPP technologies.
Prajapati et al. (2026) studied this question.