Drastic influence of the half-bowtie resonances on the focusing and collimating capabilities of 2-D extended hemielliptical and hemispherical dielectric lenses

The interplay between the optical focusing and wavelength-scale resonant features of extended hemielliptical (EHE) and extended hemispherical (EHS) lenses is studied in the two-dimensional (2-D) formulation using highly accurate in-house software based on the Muller boundary integral equations. The influence of the half-bowtie (HBT) resonances on the focusing and collimating capabilities of medium-size EHE and EHS lenses made of silicon is characterized as a function of lens parameters and excitation conditions. As a result, factors determining the parasitic impacts of the HBT resonances on the performance of integrated lens antennas are highlighted.