Highly-confined and low-loss spoof surface plasmon polaritons structure with periodic loading of trapezoidal grooves

Abstract

In this paper, we propose an ultra-thin spoof surface plasmon polaritons (SPPs) structure, periodically loaded with trapezoidal grooves. Compared to the reported SPPs with rectangular grooves, the proposed SPPs structure can support the guided surface SPP wave with enlarged propagation constant, which implies an enhanced confinement of surface wave along the spoof SPPs structure. Guided-wave characteristics of the proposed SPPs structure are theoretically investigated by virtue of a numerical short-open calibration (SOC) technique. The results show that the loss of spoof SPPs is lower than that in other reported spoof SPPs structures. Experiment on prototype in microwave frequency regime is carried out which validates the theoretical findings. It is believed that the proposed structure could be scaled to THz frequencies, and is very promising in developing the miniaturized planar surface plasmonic devices and circuitry.

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

“…For the particular case of spoof SPPs, where it is desirable to have a high attenuation in short lengths of propagation so as to reduce the depth of the grooves, the employment of radial grooves improves the ability to mimic true SPPs. This issue has also been pointed out through full-wave simulations for trapezoidal grooves [9], [10]. Alternatively, this letter provides an analysis of the radial grooves by deriving a novel dispersion relation, which also has the advantage of decreasing the computational burden of the required simulations.…”

“…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.…”

Integrated spoof plasmonic circuits

“…1c shows the first experimental demonstration of an ultrathin conformal spoof SPP TLs printed on a flexible film, where the propagation of confined spoof SPPs can adapt to the curvature of the surface [8]. Following this innovative work, TLs engraved with a variety of different ultrathin structures have been developed to support spoof SPPs, such as the trapezoidal grooves [9], oval-ring shaped cells [10], and meander slots [11], as shown in Fig. 1d-f. Dual-band trapping of spoof SPPs can be achieved through a microstrip line with periodic holes [12], as shown in Fig.…”

Novel crest‐trough shaped spoof surface plasmon polaritons for low pass filtering applications

“…Higher attenuation in short propagation lengths is desired in SSPP case; hence, employing radial grooves enhances the mimic‐ability of real SPPs with reduced depth (shallow) grooves. References and have already addressed this matter for the trapezoidal grooves by means of full wave simulations. In Reference , radial grooves has been demonstrated as a feasible configuration to efficiently support and confine SSPP with reduced groove depth in comparison to broadly used rectangular groove through analytical derivations.…”