“…The optical conductivity of graphene, a tunable parameter that can be adjusted by electrostatic bias (or chemical doping) and magnetostatic bias, plays the main role in the design and fabrication of graphene-based plasmonic devices in the THz frequencies [1][2][3]. This key feature makes graphene a fascinating material in the THz region in which many various devices have been presented and reported in the literature such as couplers [4][5][6], filters [7][8][9], resonators [10][11][12], circulators [13][14][15][16], waveguides [17][18][19][20][21][22][23][24][25][26], sensing [27][28][29][30][31][32], imaging [33,34], hyperbolic structures [35][36][37][38][39][40][41][42][43], and polarization converters [44]. Graphene-based waveguides have various structures such as planar [18,…”