Obtaining wide bandwidth with higher-order TM modes merging in a graphene-based logarithmic antenna for THz sensing applications

This paper introduces a wideband graphene material-based logarithmic antenna for THz sensing applications. The antenna consists of ten log-periodic elements which are made up of graphene material. The log-periodic antenna is excited through a silver nanostrip feedline coupled through a vias to the log-periodic elements. The proposed antenna provides wide bandwidth as well as high directivity. The antenna is operating at 1.62 THz, 2.05 THz, 2.48 THz, and 2.84 THz with wide bandwidth of 75.49 % (1.41–3.12 THz). The directivity and front-to-back ratio (FBR) are achieved as 10.16 dB and 15.12 dB, respectively. Since the bandwidth of antenna is wide which generate large number of mode. Therefore, the antenna generated higher order TM4δ (2 ≤δ≤ 8) mode. In addition, the parametric analysis has been done to obtain the impedance matching and frequency tuning by changing the external bias voltage of log-periodic graphene elements. The proposed antenna with the achieved response can be applied for THz sensing applications.