Characteristic Mode Analysis for Terahertz Plasmonic Nano-antenna Array

It is a challenge to obtain the resonance performance for the terahertz ($\mathbf{T H z}$) plasmonic antennas and their linear arrays due to the complexity of the feeding structure and vast parameters involved. This paper presents an analysis of a THz plasmonic nanoantenna array made by graphene is presented via characteristic modes theory (CM). The insightful CM theory is presented firstly to understand the resonate mechanism of the plasmonic dipole fabricated by graphene. It is validated that the mutual admittance analysis agrees well with the full-wave numerical results. This work provides a new perspective for the resonance and coupling effects of plasmonic antenna array and paves the way to design and optimization of arrays in THz regime.