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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

Dispersion curves of the new unit cell with different gaps and H-shaped unit cell in the original SPP waveguide.p is the period of the conventional unit cell as mentioned above and k is the wavenumber in the transmission line.
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f2: Dispersion curves of the new unit cell with different gaps and H-shaped unit cell in the original SPP waveguide.p is the period of the conventional unit cell as mentioned above and k is the wavenumber in the transmission line.

Mentions: Figure 2 gives the dispersion curve of the new unit cell as well as the dispersion curve of the H-shaped unit cell in the original SPP waveguide. The simulations are completed by the commercial software, CST Microwave Studio. As mentioned above, there is a certain distance between the two new unit cells. Therefore the distance gap between new unit cells was also considered in simulations. As the comparison between different dispersion curves under different values of the gap is shown, it can be observed that the cutoff frequency of the new unit cell (around 9 GHz) is much lower than that of the H-shaped unit cell (11 GHz), indicating that there is a cutoff point at around 9 GHz when the energy propagates along the designed SPP waveguide. However, the propagation will not come to an end. Owing to the gap between the new unit cells, there is a resonance caused by the capacitance. The electric-field vector at 7 GHz given in Fig. 3(a) as an example illustrates the resonance clearly. Figure 3(b) shows the electric-field vector at the same frequency for comparison. With reference to the figure, we note that there is strong electric field existing within the gaps. Although the propagation along the SPP waveguide is cutoff, the energy can be propagated through the resonance. That is the reason why there may be one more passband after the stopband. On the other hand, the traditional SPP transmission line composed of H-shaped unit cells behaves as a low-pass filter. When the slots are introduced among the unit cells, it is equivalent to introducing a stopband during the initial operating band. That is to say, the initial passband is divided into two parts by the stopband, resulting in two passbands.


Capacitive-coupled Series Spoof Surface Plasmon Polaritons.

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

Dispersion curves of the new unit cell with different gaps and H-shaped unit cell in the original SPP waveguide.p is the period of the conventional unit cell as mentioned above and k is the wavenumber in the transmission line.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Dispersion curves of the new unit cell with different gaps and H-shaped unit cell in the original SPP waveguide.p is the period of the conventional unit cell as mentioned above and k is the wavenumber in the transmission line.
Mentions: Figure 2 gives the dispersion curve of the new unit cell as well as the dispersion curve of the H-shaped unit cell in the original SPP waveguide. The simulations are completed by the commercial software, CST Microwave Studio. As mentioned above, there is a certain distance between the two new unit cells. Therefore the distance gap between new unit cells was also considered in simulations. As the comparison between different dispersion curves under different values of the gap is shown, it can be observed that the cutoff frequency of the new unit cell (around 9 GHz) is much lower than that of the H-shaped unit cell (11 GHz), indicating that there is a cutoff point at around 9 GHz when the energy propagates along the designed SPP waveguide. However, the propagation will not come to an end. Owing to the gap between the new unit cells, there is a resonance caused by the capacitance. The electric-field vector at 7 GHz given in Fig. 3(a) as an example illustrates the resonance clearly. Figure 3(b) shows the electric-field vector at the same frequency for comparison. With reference to the figure, we note that there is strong electric field existing within the gaps. Although the propagation along the SPP waveguide is cutoff, the energy can be propagated through the resonance. That is the reason why there may be one more passband after the stopband. On the other hand, the traditional SPP transmission line composed of H-shaped unit cells behaves as a low-pass filter. When the slots are introduced among the unit cells, it is equivalent to introducing a stopband during the initial operating band. That is to say, the initial passband is divided into two parts by the stopband, resulting in two passbands.

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