Terahertz wide-band band-stop plasmonic filter based on Dirac semimetal and stub resonators

As a special three-dimensional material, bulk Dirac semimetal (BDS) has flexibility and tunability, allowing the bandwidth characteristics of band stop filters to be changed by altering the Fermi level and relaxation time. In this paper, a wideband band-stop filter based on BDS-insulator-BDS waveguide using BDS is proposed for the first time. The wideband plasmonic band-stop filter was numerically and theoretically studied using the FDTD method. In order to improve the performance of the proposed filter by widening the stopband frequency, we increased the number of stub resonators. In addition, by changing the geometric parameters of the stub resonator and the distance between the stubs, the filtering range and center frequency can be modified and shifted to a larger frequency. Its maximum bandwidth increases from 0.3934 THz to 0.5289 THz when more stub resonators are introduced. Therefore, the proposed plasmonic filter dynamically adjusts the filtering frequency and bandwidth by adjusting the Fermi level of BDS, providing a flexible and effective solution.