Guiding spoof surface plasmon polaritons by infinitely thin grooved metal strip

Abstract

In this paper, the propagation characteristics of spoof surface plasmon polaritons (SPPs) on infinitely thin corrugated metal strips are theoretically analyzed. Compared with the situations of infinitely thick lateral thickness, the infinitely thin lateral thickness leads to lower plasma frequency according to the analyses. The propagation lengths and the binding capacity of the spoof SPPs are evaluated based on the derived dispersion equation. The effects of different lateral thicknesses are also investigated. At the end, a surface wave splitter is presented using infinitely thin corrugated metal strip. Other functional planar or flexible devices can also be designed using these metal strips in microwave or terahertz regimes.

Properties of spoof plasmon in thin structures

“…However, a quantitative analysis of a planar structure is needed to explain the counterintuitive red-shift occurrence in the SSPP waveguide with the reduction of the thickness of SSPP at a given propagation constant (β). Wan & Cui [27] presented a theoretical analysis of spoof plasmon in thin structures. Their analysis, however, does not predict any frequency shift or field confinement in the lower region of the SSPP band, although, in practice, the whole band undergoes red-shift with reduction of SSPP thickness as established through measurement results [15,19,20] as well as COMSOL simulation.…”

Integrated spoof plasmonic circuits

“…To obtain the Bloch wavenumber and impedance of the ultrathin corrugated metallic strip, the mode matching method from the field view is firstly investigated in Ref. [37], where an analytical solution is given for the ultrathin corrugated metallic strip. The field view indicates that this mode results from the resonance between the metallic structure and the EM wave around.…”

On the Use of Subwavelength Radial Grooves to Support Spoof Surface-Plasmon-Polariton Waves

“…Since then, the search for new possibilities to exploit the similarities between grooved metal structures and the true SPPs has been an extremely active area of research [5], [6]. For example, graded rectangular [7], thin rectangular [8], and trapezoidal grooved structures [9], [10], among others, have been proposed. The desirable properties of spoof SPPs include: a) low-frequency operation, which can facilitate dispersion [11]; c) high confinement of the fields, which is proportional to δ =(k 2 −k 2 0 ) −1/2 , with k and k 0 the propagating and space momentum, respectively; d) low dispersion, related to the group velocity and derived also from the dispersion relation; e) preservation of the original boundary, which requires shallow grooves; and f) controllability of the former properties, which means that small variations of the groove dimensions can have a significant impact on the characteristics of the SPP waves.…”