Design and Analysis of Triband Optical Nanoantenna

This paper presents the design of a triband optical nanoantenna. Initially, a straight dipole antenna is considered for a single band operation and subsequently, different arms are added to include multiple resonances. The proposed antenna operates in its fundamental mode in the lower band and higher-order modes in the middle and upper bands, respectively. The modal configuration has been identified with the help of surface current distribution, and its effect on radiation pattern null has been depicted to quantify the radiation mechanism of the proposed triband antenna. The designed antenna provides a triband frequency response with a bandwidth of 56.3, 118, and 218 THz centered around 0.2, 1.717, and 3.613 PHz, respectively. Gain of the proposed triband antenna is found to be 1.47, 3.86, and 3.27 dBi with the efficiency of 41.4, 43.7, and 54.1% at 0.2, 1.717 and 3.613 PHz, respectively. The designed antenna is found to be suitable for communication in the optical frequency regime.