Multi-fed 2-D Leaky-wave Antennas: Beam Steering and Polarization Reconfigurability

We describe the possibility of achieving enhanced radiation performance introducing multiple sources within a two-dimensional structure supporting one or more cylindrical leaky-waves. The device is planar and made by a grounded dielectric slab loaded on top by a periodic arrangement of metallic strips or patches and it is fed by an array of simple, fully integrated, dipoles. The antenna design is based on an accurate dispersive analysis of the involved leaky modes, considering solutions characterized by a fundamental fast harmonic, which can be realized using sub-wavelength partially reflecting surfaces. A design constituted by a multilayer slab of low-loss commercial laminates is proposed, and the original and attractive radiation features of the 2-D leaky-wave antennas excited by means of a circular arrangement of vertical electric or magnetic dipoles, which can effectively model several cases of practical interest, are investigated. On this basis, we demonstrate the possibility of generating either highly directional pencil beams steerable in both the azimuth and elevation far-field planes as well as the capability of controlling the polarization state of the beam.