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Capacitive-coupled Series Spoof Surface Plasmon Polaritons.

Yin JY, Ren J, Zhang HC, Zhang Q, Cui TJ - Sci Rep (2016)

Bottom Line: Two conventional H-shaped unit cells are proposed to construct a new unit cell, and every two new unit cells are separated by a gap with certain distance, which is designed to implement capacitive coupling.It is shown that the proposed structure exhibits a stopband in 9-9.5 GHz while the band-pass feature maintains in 5-9 GHz and 9.5-11 GHz.The compact size, easy fabrication and good band-pass and band-stop features make the proposed structure a promising plasmonic device in SPP communication systems.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.

ABSTRACT
A novel method to realize stopband within the operating frequency of spoof surface plasmon polaritons (SPPs) is presented. The stopband is introduced by a new kind of capacitive-coupled series spoof SPPs. Two conventional H-shaped unit cells are proposed to construct a new unit cell, and every two new unit cells are separated by a gap with certain distance, which is designed to implement capacitive coupling. The original surface impedance matching is disturbed by the capacitive coupling, leading to the stopband during the transmission of SPPs. The proposed method is verified by both numerical simulations and experiments, and the simulated and measured results have good agreements. It is shown that the proposed structure exhibits a stopband in 9-9.5 GHz while the band-pass feature maintains in 5-9 GHz and 9.5-11 GHz. In the passband, the reflection coefficient is less than -10 dB, and the transmission loss is around 3 dB; in the stopband, the reflection coefficient is -2 dB, and the transmission coefficient is less than -30 dB. The compact size, easy fabrication and good band-pass and band-stop features make the proposed structure a promising plasmonic device in SPP communication systems.

No MeSH data available.


Related in: MedlinePlus

(a) Schematic picture of the proposed structure, in which the yellow part is metal (modeled as copper, a kind of lossy metal, the conductivity of which is 5.8 × 107 S/m) and the blue part is dielectric substrate. (b) Prototype of the proposed structure.
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f1: (a) Schematic picture of the proposed structure, in which the yellow part is metal (modeled as copper, a kind of lossy metal, the conductivity of which is 5.8 × 107 S/m) and the blue part is dielectric substrate. (b) Prototype of the proposed structure.

Mentions: As shown in Fig. 1(a), the proposed structure is designed on a 0.5 mm-thick substrate with permittivity 2.65 and loss tangent 0.003. The overall size is 349 × 51.1 mm2, with the thickness of the metal film is set as 0.018 mm. To achieve the broadband impedance matching, the CPW part (Part I) is designed with the width of central conductor as 10 mm and the gap between the central conductor and ground as 0.55 mm, to realize the 50-ohm impedance. The conversion part (Part II) from CPW to the SPP waveguide is similar to that in ref. 15, in which the gradient groove depth varies from zero to 4 mm, to reach the broadband momentum matching, and the optimized curve of flaring ground is described as an exponential function (y = C1eαx + C2, α = 0.1, where C1 and C2 are determined by the length of the Part II and the width of the flaring ground) for impedance matching simultaneously. The overall length of Part II is 60 mm while the width of the flaring ground is set as 20 mm. As spoof SPPs appear along the transmission line after the conversion from spatial modes in CPW, the capacitive coupling should be designed. Every two H-shaped unit cells of the SPP waveguide is regarded as a new unit cell in this particular design. The dimensions of the original SPP unit cell are p = 5 mm, a = 2 mm, and h = 4 mm, denoting the period, width, and depth of grooves, respectively. Every two new unit cells are separated by a gap with certain distance of g = 0.1 mm after optimization, which can be equivalent to a capacitance. The capacitance added here will bring about a stopband within the operating frequencies of the original SPP waveguide due to the mismatch of the surface impedance.


Capacitive-coupled Series Spoof Surface Plasmon Polaritons.

Yin JY, Ren J, Zhang HC, Zhang Q, Cui TJ - Sci Rep (2016)

(a) Schematic picture of the proposed structure, in which the yellow part is metal (modeled as copper, a kind of lossy metal, the conductivity of which is 5.8 × 107 S/m) and the blue part is dielectric substrate. (b) Prototype of the proposed structure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835726&req=5

f1: (a) Schematic picture of the proposed structure, in which the yellow part is metal (modeled as copper, a kind of lossy metal, the conductivity of which is 5.8 × 107 S/m) and the blue part is dielectric substrate. (b) Prototype of the proposed structure.
Mentions: As shown in Fig. 1(a), the proposed structure is designed on a 0.5 mm-thick substrate with permittivity 2.65 and loss tangent 0.003. The overall size is 349 × 51.1 mm2, with the thickness of the metal film is set as 0.018 mm. To achieve the broadband impedance matching, the CPW part (Part I) is designed with the width of central conductor as 10 mm and the gap between the central conductor and ground as 0.55 mm, to realize the 50-ohm impedance. The conversion part (Part II) from CPW to the SPP waveguide is similar to that in ref. 15, in which the gradient groove depth varies from zero to 4 mm, to reach the broadband momentum matching, and the optimized curve of flaring ground is described as an exponential function (y = C1eαx + C2, α = 0.1, where C1 and C2 are determined by the length of the Part II and the width of the flaring ground) for impedance matching simultaneously. The overall length of Part II is 60 mm while the width of the flaring ground is set as 20 mm. As spoof SPPs appear along the transmission line after the conversion from spatial modes in CPW, the capacitive coupling should be designed. Every two H-shaped unit cells of the SPP waveguide is regarded as a new unit cell in this particular design. The dimensions of the original SPP unit cell are p = 5 mm, a = 2 mm, and h = 4 mm, denoting the period, width, and depth of grooves, respectively. Every two new unit cells are separated by a gap with certain distance of g = 0.1 mm after optimization, which can be equivalent to a capacitance. The capacitance added here will bring about a stopband within the operating frequencies of the original SPP waveguide due to the mismatch of the surface impedance.

Bottom Line: Two conventional H-shaped unit cells are proposed to construct a new unit cell, and every two new unit cells are separated by a gap with certain distance, which is designed to implement capacitive coupling.It is shown that the proposed structure exhibits a stopband in 9-9.5 GHz while the band-pass feature maintains in 5-9 GHz and 9.5-11 GHz.The compact size, easy fabrication and good band-pass and band-stop features make the proposed structure a promising plasmonic device in SPP communication systems.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China.

ABSTRACT
A novel method to realize stopband within the operating frequency of spoof surface plasmon polaritons (SPPs) is presented. The stopband is introduced by a new kind of capacitive-coupled series spoof SPPs. Two conventional H-shaped unit cells are proposed to construct a new unit cell, and every two new unit cells are separated by a gap with certain distance, which is designed to implement capacitive coupling. The original surface impedance matching is disturbed by the capacitive coupling, leading to the stopband during the transmission of SPPs. The proposed method is verified by both numerical simulations and experiments, and the simulated and measured results have good agreements. It is shown that the proposed structure exhibits a stopband in 9-9.5 GHz while the band-pass feature maintains in 5-9 GHz and 9.5-11 GHz. In the passband, the reflection coefficient is less than -10 dB, and the transmission loss is around 3 dB; in the stopband, the reflection coefficient is -2 dB, and the transmission coefficient is less than -30 dB. The compact size, easy fabrication and good band-pass and band-stop features make the proposed structure a promising plasmonic device in SPP communication systems.

No MeSH data available.


Related in: MedlinePlus