Improving the Scanning Coverage of Array Antennas With Multilayer Lenses Designed With a Ray Tracing

Integrating dielectric lenses with phased array antennas can be beneficial in numerous applications, yet the design procedure typically requires significant computational effort. In this work, we employ a streamlined in-house 2-D ray-tracing model to design dielectric lenses, with the goal of enhancing the gain of an array antenna at large scanning angles. The ray-tracing model also accounts for losses from material absorption and reflections. The interfaces between the dielectric layers of these lenses devised in this study are defined using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">splines</i> to allow a large flexibility of their shape. First, dielectric lenses consisting of a core layer supplemented by two matching layers are investigated. The results show better performance compared to the lens constructed using the conic equation. In addition, multilayer dielectric lenses also provide more flexibility, as proved by the proposed configuration with five layers which also minimizes reflections in the optimized direction. Finally, a nonuniform multilayer lens, featuring two layers on the sides and a single layer near to broadside can improve gain at 60<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> while maintaining efficiency at smaller angles.