On Biconvex Lens, its Scanning Properties and Application in Multibeam Antenna Arrays

In this paper, beam scanning properties of a constant-index biconvex (BC) lens are explored. It is shown that changing the lens geometry from plano-convex (PC) to BC while maintaining constant focal length, lens aperture, and thickness leads to a 2.1 times increase in the scanning angle (from ± 18.11° to ± 38.14°) and a 4.3 times increase in the scanning solid angle (from 0.31 sr to 1.34 sr). The utilization of the BC lens also results in a lower lens volume and the overall size of lens antennas, however, at the expense of a maximum gain reduction that is not greater than 2.9 dB. The proposed lenses were printed on a 3D printer and the concept has been validated by the measurements of four-beam lens antenna arrays operating at 24 GHz.