  This letter proposes a new spoof surface plasmon transmission line (SSP-TL)
using capacitor loading techniques. This new SSP-TL features flexible and
reconfigurable dispersion control and highly selective filtering performance
without resorting to configuration change. Moreover, it requires much smaller
line width than the conventional SSP-TLs for achieving a extremely slow wave
(or a highly confined field), which is quite useful for a compact system. To
illustrate the design principle, several examples are designed within the
frequency range of 2-8 GHz. Both numerical and experimental results are given
in comparison with the conventional SSP-TL. It is demonstrated that the
proposed technique provides a better performance in size reduction and
dispersion reconfigurability.
