Design of Graphene-Based Rat-Race Coupler in THz band

This paper presents the design for a rat-race coupler and design equations for THz band applications is presented. The S-parameter of proposed structure is calculated. The design procedure begins with design of a rat-race coupler in 12 GHz and PEC structure. Then the calculated values are transformed to THz band by design equations that are also described. The results from both PEC and graphene are shown that the proposed structure operates as a coupler for summing and subtracting the input signals.