Spoof surface plasmon polaritons transmission lines with line-width reduction based on miniature unit structures

In this letter, two miniature spoof surface plasmon polaritons (SSPPs) unit structures are proposed. A trident-shaped groove and a Jerusalem cross-shaped groove are respectively designed to increase the equivalent depth of the groove so as to realize the reduction of the line-width. With smaller size, the proposed units have the equivalent dispersion of classical unit. To validate the properties of the proposed units, SSPPs transmission lines (TLs) are designed. Compared with the classical rectangular grooved SSPPs TL, the proposed unit with trident-shaped groove and Jerusalem cross-shaped groove can achieve the similar transmission performance with a line-width reduction of 44.4% and 19.1%, respectively. The measured results of TLs agree well with the simulated ones, which validates the designs. Moreover, the proposed unit structures confine field more effectively. The proposed structures are attractive and useful for the miniaturization of SSPPs devices.