Analysis of Dielectric Lens - Adaptive Array Antennas for Shaped Beam Applications

Small adaptive arrays embedded in a dielectric lens are cost effective and inherently broadband at producing highly shaped beams critical to mobile broadband applications (MBS). In this paper an accurate analytical formulation based on spherical modal expansion (SME) of the near fields of small apertures radiating in the presence of a shaped dielectric lens is presented. The analysis treats the lens as a scatterer. It utilizes techniques for radial translation and coordinate rotation of the small aperture spherical modal coefficients to align them to the phase center of the dielectric lens. The spherical modal coefficients of the scattered fields due to the lens are then obtained by application of boundary conditions. A sample computation is performed to demonstrate the approach and supported by an experimental result. The analysis is flexible enough to accommodate different types of small radiating apertures and different shapes for the dielectric lenses.