Inhomogeneous Dielectric Lens Antennas Design based on Clothoid Ray Paths

In this paper we present a novel approach for the design of inhomogeneous lenses based on clothoid ray paths. Among various possible choices, Clothoids are a type of curves which present the advantage to control their curvature. Given the illuminating and the target aperture distributions of the field on both sides of the lens, the proposed technique consists first in a "ray tracing" inside the lens volume; the exact ray paths can be adjusted to reach a minimum curvature ray congruence. Then, through a subsequent "phase tracing" algorithm, the wavefronts are traced inside the lens and refractive index distribution is finally retrieved. The lens design algorithm is presented in details and some inhomogeneous lens examples are given.