We propose and analyze a graphene electromagnetic filter for the terahertz (THz) region. The filter represents a planar square array of graphene elements. A unit cell of the array is formed by two coaxial graphene rings placed on the opposite sides of a thin dielectric substrate. The two electromagnetically coupled rings resonate with dipole plasmonic modes. The rings have slightly different dimensions and consequently different yet close individual resonant frequencies. At a frequency lying between these two resonances, the currents in the two interacting rings have opposite directions. This leads to a suppression of the reflected from the array waves and consequently to a high transmission through the array. For the chemical potential of the graphene μc=0.6 eV, the calculated quality factor of this resonant mode is Q=5 at the frequency f=0.8 THz. At this frequency, the reflection coefficient of the array equals -36 dB and the transmission peak which is defined by the graphene losses is -1.8 dB. We show that the frequency position of the transmission peak can be varied in a wide range by the graphene chemical potential.
ABSTRACT:Carbon nanotubes are possible building blocks in the development of new generation of electronic devices. The carbon nanotubes allow one fabrication of devices using nanometric scales. They can be used in projects of a wide range of electronic and optoelectronic components such as diodes, transistors and interconnection elements, among others. This paper presents the state-of-the-art of this area, emphasizing the influence of quantum effects on the characteristics of such components.
In this work, we propose and numerically analyze a new electromagnetic polarization filter in THz region based on graphene fish-scale structure. The array is composed by graphene strips placed on a metallized dielectric substrate. The filter can operate in two different frequency regions that can be shifted in frequency by appropriate choice of width of the graphene ribbons. We present as an example, at f 1 5 0.483 THz, the structure possesses the reflection coefficient of 20.38 dB for the incident waves with x-polarization and 248.05dB for the y-polarized ones, while at f 2 5 0.792 THz, the reflection coefficients are 247.25 dB for x-polarization and 20.86 dB for y-polarization. The physics of the device is based on surface plasmon polariton (SPP) resonances in the graphene. The central frequency can be dynamically adjusted by changing the chemical potential (ie, by an external voltage for example) of the graphene strips. K E Y W O R D S fish-scale, grapheme, polarization filter, polarizer, surface plasmon polariton
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