BroadBand spoof surface plasmon polaritons coupler based on dispersion engineering of metamaterials

Abstract

The dispersion curves of spoof surface plasmon polaritons (SSPPs) are typically asymptotically nonlinear, with only one single intersection point with the dispersion curves of couplers. This means that wave-vector matching can be achieved only at a single frequency, leading to a narrow bandwidth of SSPP couplers. In this letter, we propose to achieve broadband SSPP couplers through dispersion engineering of metamaterials. To this end, we investigated the dispersion properties of a metallic patch array (MPA) that supports the propagation of TE-mode SSPPs at microwave frequencies. After this, we designed a planar metamaterial lens that can provide additional tangential wave-vectors to free space waves. By dispersion engineering, the dispersion curve of the coupled waves overlaps with that of SSPPs on the MPA in a broadband, resulting in high-efficiency broadband coupling of SSPPs. As an example, we demonstrated a broadband SSPP coupler with more than a bandwidth of 1 GHz in the X band. The method can be readily extended to millimeter-wave, terahertz, and other higher frequencies.

Wireless Experimental Determination of Dispersion Curves of Spoof Surface Plasmon Polariton Modes Supported by a Transmission Line

“…Such a surface wave mimics the surface plasmon polariton (SPP) commonly used in plasmonics, and then it is called spoof surface plasmon polariton (SSPP). [ 1 ] Different structured surfaces were proposed for guiding SSPP as conducting surfaces perforated by holes, [ 2 ] mushroom structures, [ 3,4 ] metasurfaces made of square or rectangular patches, [ 5,6 ] and periodic chains of laterally opened, [ 7,8 ] or closed [ 9 ] metallic cuboids (“dominos”). The mushroom‐ and patch‐based structures are commonly considered as an effective impedance surface supporting transverse magnetic (TM) and transverse electric (TE) modes.…”

“…The mushroom-and patch-based structures are commonly considered as an effective impedance surface supporting transverse magnetic (TM) and transverse electric (TE) modes. [3][4][5][6]10] A bound TM mode can also be supported by a periodic chain of cuboids. It was experimentally shown that the dispersion curve is invariant with the lateral width of the cuboids [7] and that the dispersion curve moves slightly downward by reducing the lateral size of a metallic grating structure down to subwavelength scale.…”

“…As a generality, the electromagnetic field confinement is achieved when the magnitude of the wave vector k of the SSPP is greater than the wave vector in free space k 0 . Depending on the involved technology for the surface waveguide, a wave vector converter [5,6] or a taper [15,19,[23][24][25] is often required to convert incident wave to SSPP. [26] An SSPP can also be excited by means of nearfield coupling with a prism in Otto configuration [3,4] or by nearfield coupling with a monopole antenna.…”

Novel Dual-band Band-Pass Filters Based on Surface Plasmon Polariton-like Propagation Induced by Structural Dispersion of Substrate Integrated Waveguide

“…One of the concepts that effectively mimics SPPs are spoof or designer surface plasmon polaritons 6 , 7 , which have been widely used in different microwave circuits including transmission lines 8 – 16 , filters 17 – 26 , antennas 27 , couplers 28 , splitters 29 , absorbers 30 , and circulators 31 . Unlike genuine SPPs, spoof SPPs are supported by specifically designed structures, predominantly by grooved strips whose geometrical properties are used to tailor the behaviour of spoof SPPs.…”

Full‐Polarization Frequency Controlled Multimode Spoof Surface Plasmon Polaritons Excitation via Anisotropic Metastructure

“…[19][20][21][22][23][24] Heretofore, diverse couplers, the precondition of SSPPs' excitation, have been designed to generate the desired phase gradient along the propagating directions. [15,[25][26][27][28][29] Then, the dispersion of the propagating metasurfaces (PMs) is meticulously designed to couple with the coupler's, transforming incident EM waves into the surface waves. There are two common types of couplers-transmission structure and reflection structure, both of them have been proposed to realize high-efficient performance in SSPPs.…”