Dispersion engineering of spoof plasmonic metamaterials via interdigital capacitance structures

This work presents an approach to realize the dispersion engineering of spoof plasmonic metamaterials with control-lable cutoff frequencies. Interdigital capacitance structures are applied to construct the unit cells. Dispersion properties are firstly analyzed to investigate the effects of interdigital capacitance, and the influence of the geometrical parameters of the proposed unit cell on the cutoff frequencies is studied. Then, a spoof surface plasmon polariton (SSPP) transmis-sion line (TL) is developed based on the proposed unit cell together with a smooth transition. The matching principles of the transition are explained by the dispersion curves and the normalized impedance of the corresponding matching unit cells. Finally, the transmission characteristics of the TL are simulated and measured to validate the feasibility of the proposed strategy. Both the lower and upper cutoff frequencies can be tuned jointly by the extra degrees of free-dom provided by the interdigital capacitance structures. In comparison with designs based on a substrate-integrated waveguide (SIW), the proposed strategy can reduce the transversal dimension by a factor of two under the same con-ditions. This work can greatly accelerate the development of versatile microwave integrated circuits and systems based on spoof plasmonic metamaterials. (c) 2023 Optica Publishing Group

Automated summary

This work proposes an approach to achieve dispersion engineering of spoof plasmonic metamaterials with adjustable cutoff frequencies. Interdigital capacitance structures are used to construct unit cells. The dispersion properties and the influence of unit cell parameters on cutoff frequencies are analyzed. A spoof surface plasmon polariton (SSPP) transmission line (TL) is developed based on the proposed unit cell and a smooth transition. The feasibility of the strategy is validated through simulation and measurement of the TL's transmission characteristics. The proposed approach can greatly enhance the development of versatile microwave integrated circuits and systems based on spoof plasmonic metamaterials.