Performance predictions of slotted graphene patch antenna for multi-band operation in terahertz regime

•A single element antenna is designed with compact size, which offers multiband performance at terahertz frequency range.•Initially, a graphene based patch radiator is designed using silica substrate at 1.9THz for efficient transmission of terahertz waves.•Then, a square-shaped slot is embedded in the radiating patch for antenna miniaturization to produce additional resonance at 4.83THz.•Finally, the ground plane length is reduced and a square shaped slot is inserted in the center of the ground plane to produce resonance at 5.5THz.•Thus, a single element multi-band antenna which operates at three different frequencies such as 1.96THz, 4.83THz and 5.5THz is designed for the first time at terahertz frequency range. A compact multi-band graphene based patch antenna is proposed for THz applications. A single band antenna is initially designed without slot, where the lower resonant mode of the antenna operates only at single frequency of 1.9 THz with a bandwidth of 50 GHz. Dual-bands are realized by introducing slots in the graphene patch. The proposed structure makes the antenna simple in design and easy for fabrication by employing slots in the graphene patch. By adjusting the position of the slot in the patch, the antenna is made to radiate at dual frequencies of 1.96 THz and 4.83 THz with bandwidths of 80 GHz and 100 GHz respectively. FDTD based EM simulation predicts a return loss of -34 dB and-38 dB at 1.96 THz and 4.83 THz respectively and VSWR less than 1.5 at both frequency bands. Moreover, the antenna provides a significant gain of 4.75 dB and 4.3 dB over the operating bands and efficiency greater than 92 % is observed. Further, the antenna is made to operate at triple bands of 1.96 THz, 4.83 THz and 5.55 THz by introducing defects in the ground plane.