ABSTRACT
This chapter presents near-field and far-field characteristics of nanoantenna networks and showed that signal propagation can be performed using diverse architectures. Nanoantennas refer to nanoscale transducers that convert electric energy into electromagnetic (EM) wave propagation as a transmitting antenna in a communication channel, with low energy loss, working at optical frequencies. EM radiation from nanoantenna induces near-field distribution on a wavelength spatial scale, which undergoes transition from Fresnel region into far-field propagation. Yagi–Uda designs have been extremely popular for optical nanoantennas; that is, arranging metal nanostructures at sufficiently narrow intervals can induce signal propagation by coupling plasmonic waves between the metals. Network characteristics can be modulated by varying antenna parameters, including the geometry of metallic and dielectric nanoantennas. The nanoantennas based on nonpropagating near fields are largely metallic, with plasmonic effects; however, dielectric nanoantennas are also feasible.
