Beam-steering of dielectric flat lens nanoantenna with elliptical patch based on antenna displacement for optical...

In this paper, the switched-beam nanoantenna (NA) concept is introduced with a theoretical design of an inhomogeneous dielectric flat lens modelled with different materials to steer and enhance the radiation in a particular direction based on shifting the illuminator element. Firstly, the design of hybrid plasmonic NA is introduced and analyzed considering different silicon patch shapes such as rectangular, circular, hexagonal, and elliptical shapes. The elliptical patch NA achieves a gain of up to 10.7 dBi and a return loss of - 14.41 dB. Then the design of a gradient-index dielectric flat lens with the NA is introduced to improve the antenna performance by increasing the directivity and consequently decreasing the beam-width. Furthermore, the beam-steering capabilities by displacement of the NA according to different feeding points along the X and Y-direction. By using the gradient-index dielectric flat lens, the gain is increased to 18.4 dBi with an improvement in the return loss reach to - 19.15 dB compared with traditional NA. In addition, the beam-steering capabilities were achieved with a range ± 60° ×  ± 55° with acceptable average antenna gain, side-lobe levels, and half power beam-width of 16.5 dBi, - 12.3 dB and 13.6° respectively.