This work deals with the efficient analysis of linear arrays of cavity-backed slot antennas. The considered array elements can be single or multiple slots radiating in the presence of a rectangular cavity. A spectral method of moments (MoM) is used to estimate the impedance and the patterns of the slot array. The method is rendered computationally efficient by considering, for each slot, only two basis functions that suitably describe the magnetic current distribution. The first basis function is derived by solving the auxiliary problem where only the cavity walls parallel to the slot axes are considered. The second basis function is obtained by solving the problem of a closed rectangular cavity excited by a magnetic current distributed on the slot region. The proposed method allows to simulate entire finite arrays in a few seconds per frequency point and can be exploited to aid the design and optimization of cavity-backed slot arrays.

We introduce the design of an array-fed dielectric lens antenna that enables electronic beam steering within a large Field of View (FoV). The feed array consists of eight cavity-backed double-slot antenna elements, fed by a microstrip feed structure that tilts the beam of each double slot toward the lens center. The slots are loaded with a two Artificial Dielectric Layers (ADL) to increase the front-to-back ratio. The elements are placed closer to the lens surface with respect to the nominal focal plane and are combined with proper weights to reduce the scan loss. Metallic reflectors are positioned along the sides of the array edges to further improve the scanning performance, especially at large scan angles. Full-wave simulations show that the designed antenna realizes a stable gain around 20 dBi within a ±50° FoV coverage, for a lens diameter of 5 wavelengths.