Spoof surface plasmonics: principle, design, and applications

Abstract

Surface plasmon polaritons (SPPs) are interactions between incident electromagnetic (EM) waves and free electrons on the metal-dielectric interface in the optical regime. To mimic SPPs in the microwave frequency, spoof SPPs (SSPPs) on ultrathin and flexible corrugated metallic strips were proposed and designed, which also inherit the advantages of lightweight, conformal, low profile, and easy integration with the traditional microwave circuits. In this paper, we review the recent development of SSPPs, including the basic concept, design principle, and applications along with the development from unwieldy waveguides to ultrathin transmission lines. The design schemes from passive and active devices to SSPP systems are presented respectively. For the passive SSPP devices, the related applications including filters, splitters, combiners, couplers, topological SSPPs, and radiations introduced. For the active SSPP devices, from the perspectives of transmission and radiation, we present a series of active SSPP devices with diversity and flexibility, including filtering, amplification, attenuation, nonlinearity, and leaky-wave radiations. Finally, several microwave systems based on SSPPs are reported, showing their unique advantages. The future directions and potential applications of the ultra-thin SSPP structures in the microwave and millimeter-wave regions are discussed.

Fabrication and characterization of delay lines with spoof surface plasmon polariton waveguide coupled with C-shaped metamaterials for microwave integrated circuits

“…11(b) also indicates that the phase difference between the ON and OFF devices is caused by the dispersion relationship due to the existence of surface plasmon polaritons. 38) Compared to light propagation in free space [the light line in Fig. 11(b)], microwaves propagate with a slower phase velocity in the waveguide.…”

Meta-optics inspired surface plasmon devices

“…Nevertheless, benefiting from the well-established semiconductor processing technology and printed circuit board technology, it is much more convenient to fabricate sophisticated samples in the THz and microwave regimes; moreover, the characterization methods at lower frequencies are capable of obtaining the full amplitude and phase information as well as exacting spatiotemporal dynamics of SP fields, which can hardly be obtained in the IR and visible ranges. Studies of SPs at THz and microwave frequencies could explore general underlying physics, which are applicable to IR and visible frequencies, but can hardly be directly investigated at these frequencies due to limitations of current technology [14,15,101–103] . Therefore, this review also covers SP devices at THz and microwave frequencies.…”

“…3(h)]. Another solution is constructing subwavelength periodic structures on metal surfaces to apply the spoof SPP concept [14,101,102] , discussed in detail later. In 2015, Ng et al adopted the Otto prism configuration [Fig.…”

In-Plane Radiation of Surface Plasmon Polaritons Excited by Free Electrons

“…As opposed to transformation to Cherenkov radiation, the most important feature of the transformation to SPR via periodic structures is the absence of a threshold requirement for electron velocity. As a supplement to conventional gratings, various metasurfaces or metamaterials are increasingly being applied to the study of the conversion of localized fields into radiation [ 33 , 34 ]. In 2015, Tiejun Cui et al proposed a method in which a link is established between SPP waves and radiation waves in a highly controllable way using ultrathin corrugated metallic strips, opening up an avenue for designing new kinds of microwave and optical elements in engineering [ 35 ].…”