Design and Performance Evaluation of Single- and Multi-Element THz Nanoantennas using Graphene as the Radiating Patch

ABSTRACT Recently, there is an increasing interest in graphene-based antenna for terahertz (THz) applications. The graphene is characterized by high conductivity in this band and has resonance frequency tunability by applying bias voltage. This paper addresses the possibility of using the graphene as the radiating element in sub-100 THz band to design single-element and phase array nanoantennas. The nanoantenna structure that uses graphene as the radiating element is investigated using CST software package version 2016. This antenna has dipole-shaped graphene radiating element and operates at 35 THz. The antenna design is based on silicon dioxide substrate with the radiating element on its top side surface and a gold reflector at its bottom side. The resonance frequency, radiation efficiency, and the gain of the antenna are studied for different dimensional parameters and various chemical potentials of the graphene patch. The results reveal that the graphene chemical potential (?c) has a large impact on the antenna resonance frequency (fr). Increasing ?c from 0.1 to 1 eV will increase fr by 240% for the dipole antenna. The radiation pattern performance of phase array antenna (PAA) made of the dipole nanoantenna is also simulated. The radiation parameters, namely steering angle, beam width, and gain, are evaluated for different phase shifts and element spacing. The results show that steering angle increases with phase difference and reaches 12.9 and 33 degree for 50 nm and 250 nm spacing at 80 degree phase difference for 4 × 1 configuration, respectively. The beam width decreases with phase difference while the gain is almost insensitive to phase difference. Keywords: THz antenna; Graphene THz antenna; Nanoantenna.