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We propose analytical and numerical modeling of a tunable electromagnetic dual‐band filter based on a periodic structure of black phosphorus (BP) discs deposited on silicon dioxide for operating in terahertz and infrared regions. Due to BP anisotropy, single operation dipole mode bands for polarization of incident wave in the armchair or zigzag directions exist. These bands correspond to different resonant frequencies. However, for another polarization, in particular, for a 4 5 ∘ $4{5}^{\circ }$ polarization, a double operation band appears. The dynamic control of the proposed structure can be performed by varying the electronic doping of the BP, thus changing the operating frequency of the filter. The analytical model based on the temporal coupled‐mode theory is in good agreement with the numerical simulations by COMSOL Multiphysics.

We propose and analyze a multifunctional THz graphene-based component with graphene elements placed on a dielectric substrate. The structure of the device consists of a disc shaped resonator coupled to three graphene waveguides that excite the dipole or quadrupole resonance of surface plasmon polaritons in the resonator. The graphene resonator can be magnetized by a DC magnetic field. This device fulfills filtering of the input signal and can be used as a power divider and also as a switch. The division mechanism of the T-junction can be provided by application of a DC magnetic field or by changing the Fermi energy of the graphene resonator via an electrostatic field. Some peculiarities of the two mechanisms are discussed. Numerical simulations show that for a central frequency of 7.12 THz, devices in the OFF state have the two output ports isolated from the input port at a central frequency of about 27 dB provided by the dipole mode resonance. In the ON state and the division regime, the transmission to the output ports is around − ( 4 ÷ 5 ) d B in the 3-dB bandwidth of about 12%.

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