SSPPs-based Low-pass Filter with Continuously Adjustable Cut-off Frequency

In this paper, a microwave filter with tunable cutoff frequency is proposed based on spoof surface plasmon polaritons (SSPPs) structure. The adjustable filter is proposed by adding metal branches controlled by varactors which can be changed through different bias. The simulated results show that the filter has different dispersion characteristics and exhibits low-pass bands with different cut-off frequencies. The proposed active adjustable filter is expected to play a potential role in modern communication system.