Wideband Miniaturized Design of Complementary Spoof Surface Plasmon Polaritons Waveguide Based on Interdigital Structures

Abstract

In this paper, we present to achieve a broadband miniaturized transmission waveguide based on complementary spoof surface plasmon polaritons (CSSPPs). For this purpose, a novel SSPP design that consists of a corrugated slot line and a group of additional interdigital structures (ISs) is proposed, which brings in an extra solution to control the cutoff property of CSSPPs. The transmission cutoff frequency of the proposed design decreases with the increasing of the number of the ISs. Since the width of CSSPP waveguide is directly related to the operating frequency, the degree of miniaturization can be modulated freely by carefully choosing the number of the ISs. A prototype of device with four-ISs introduced is designed and fabricated. And the cutoff frequency of the design decreases from 10 GHz to 5.3 GHz, when the ISs are added. Experimental results agree well with the numerical simulations. The proposed design illustrates great potentials in modern plasmonic integrated circuits. Surface plasmon polaritons (SPPs) are classical surface modes excited along interface of metal and dielectric at visible and near-infrared wavelengths 1,2. Such modes exhibit significant properties of near-field confinement, shorter operating wavelength and perfect low-pass transmission, which have been studied in a broad range of applications such as high-resolution imaging 3-6 , electromagnetically induced transparency (EIT) 7-9 , photovoltaic improvement and biosensing 10-13. However, in the longer-wavelength spectra, like microwave and terahertz waves, SPP mode cannot be excited directly, due to the perfect-electrical-conductor property of metal. And the traditional Sommerfield-Zenneck surface electromagnetic responses show weak field-confinement 14. In order to take advantages of the significant properties of SPP modes in the lower frequencies in high-efficient and less-mutual-coupling applications, metamaterials are introduced to achieve novel surface responses that have similar dispersive properties with SPP modes-the spoof SPP (SSPP) mode. In 2004 and 2005, Pendry et al. and Hibbins et al. predicted theoretically and verified experimentally such SSPP surface mode on the surface with periodic subwavelength cubic holes 15,16. Then a series of plasmonic designs have been reported to obtain the SSPP waves at both microwave and terahertz frequencies 17-20. High-order SSPP mode along corrugated metallic strip was also studied to achieve extra working bands 21. And spoof surface magnon polaritons was theoretically analyzed along corrugated PMC surface 22. In order to excite the SSPP mode efficiently, the dispersion properties related to geometry dimensions and field distribution in both homogeneous and inhomogeneous media are studied 23-25. A series of matching approaches were reported to connect the SSPP waveguides and traditional transmission lines 26-30. High-efficient transmissions of SSPP mode were experimental excited via co-planar waveguides, microstrip lines, and corrugated slot lines. Based on these designs, plenty of functiona...

Design of compact and broadband filtering balun based on N-shaped spoof surface plasmon polaritons

“…11 (b) depicts their simulated 1-D electric-field distributions along the zdirection at 3 GHz. It can be seen that Balun B's electric field decays faster perpendicular to the propagation direction than that of Balun C. The results in Fig.11indicate that Balun B has a stronger field-confined ability than Balun C, which is attributed to the larger phase constant of the N-shaped SSPP unit cell at 3 GHz [29,30]…”

Ultra-Compact Low-Pass Spoof Surface Plasmon Polariton Filter Based on Interdigital Structure

“…A spoof surface plasmon polariton (SSPP) can be excited from a metal plate with periodic holes, slots, rings or varactor diodes in the terahertz and microwave bands, and its propagation and attenuation characteristics are similar to those of an SPP [ 7 , 8 , 9 , 10 , 11 , 12 ]. Therefore, the SSPP structure has been applied in several microwave/terahertz devices including antennas [ 13 , 14 , 15 , 16 ], waveguides [ 17 , 18 , 19 ], power splitters/combiners [ 20 , 21 , 22 ] and various filters [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

High Q‐factor anapole mode based on localized spoof surface plasmon polaritons

“…Surface plasmon polaritons (SPPs) are an electromagnetic response that becomes evident when free excited electrons in metals interact with the optical wave and spread at the interfacing between metals and dielectric materials. SPPs provide solutions to overcome diffraction limits that can miniaturize the optical components 1 . In the past, SPPs were studied only in the visible or ultraviolet (UV) frequency band but in 2014 Pendry et al proposed a subwavelength structure consisting of square hole arrays to produce the dispersion analogous to the natural SPPs at microwave frequency; such an electromagnetic response is called the spoof SPPs.…”

“…SPPs provide solutions to overcome diffraction limits that can miniaturize the optical components. 1 In the past, SPPs were studied only in the visible or ultraviolet (UV) frequency band but in 2014 Pendry et al proposed a subwavelength structure consisting of square hole arrays to produce the dispersion analogous to the natural SPPs at microwave frequency; such an electromagnetic response is called the spoof SPPs. The concept of spoof SPPs helps to miniaturize the integrated circuits and enhance the field confinement, which helps in many potential applications in lasing, 2 filters, 3 waveguides, 4 devices, 5 and sensing, 6,7 and so on.…”