Terahertz On-chip Tunable Spoof Surface Plasmon Polaritons Transmission Lines Based on Vanadium Dioxide

In this paper, we propose a tunable terahertz on-chip spoof surface plasmon polaritons transmission line (SSPPs TL) based on the insulating-conducting phase transition property of vanadium dioxide (VO
2
). The dispersion characteristics of the on-chip SSPPs unit is simulated under the
$0.25-\mu \mathrm{m}$
InP DHBT technology, and the transition from GCPW to SSPPs TL is realized by using the gradient grooves. In the design, the top and bottom layer of the VO
2
film are connected to the M1 and M3, respectively, to achieve the dynamic manipulation of insertion loss
$S_{21}$
of the SSPPs TL. When the VO
2
is insulating, the
$S_{21}$
of the SSPPs TL is better than 4 dB from the frequency range of 100 GHz to 500 GHz. Alternatively, when the VO
2
is in the conducting state, the
$S_{21}$
of the SSPPs TL is larger than 18 dB. This work may have extensive potential applications in integrated terahertz plasmonic dynamic devices.