Theoretical Analysis of a Super-Mode Waveguide and Design of a Complementary Triangular Hybrid Plasmonic Nano-Antenna

Abstract

The characteristics of a super-mode waveguide-fed nano-antenna composed of a complementary triangular hybrid plasmonic radiation part have been investigated by two methods of finite element and finite-difference time-domain. Also, a symmetric hybrid plasmonic waveguide (SHPW) has been studied theoretically and numerically to analyze short- and long-range fundamental TM super-modes (TMSR and TMLR) that excite the nano-antenna. The obtained propagation length and figure of merit at 193.5 THz are 150.6 μm (1.27 μm) and 691.77 (16.94) for TMLR (TMSR) super-mode, respectively, which confirm the inevitable loss-confinement trade-off of SHPW. These super-modes cause the nano-antenna to have horizontal and bidirectional radiation patterns due to the existence of the in-phase and out-of phase super-modes. The obtained directivities and efficiencies are 9.34 dBi (7.01 dBi) and 96.82% (9.66%) for TMLR (TMSR) super-mode, respectively, at 193.5 THz. Moreover, the horizontal and bidirectional radiation patterns are appropriate for on-chip wireless links with the quality factor of 69.18 and target tracking systems, respectively. The performance of a single row array of nano-antenna on improving the directivity and efficiency has been studied. The proposed SHPW-fed nano-antenna is quite tolerant to practical fabrication errors and compatible with lift-off and electron beam lithography fabrication processes.