Wideband array-fed Fabry-Perot cavity antenna for 2-D beam steering

We propose the design and test of a 2-D Fabry-Perot structure based on a multilayer slab arrangement fed by a circular array of simple sources. Such a class of planar leaky-wave antenna can be made by low-loss commercial laminates and it is bounded on top by a sub-wavelength partially-reflecting surface. The antenna is designed to suppress undesired radiation from the quasi-TEM mode while leaking power by the excitation of a fast TM1 leaky mode, which is a perturbed version of the guided-wave supported by the corresponding parallel-plate waveguide. An accurate dispersive analysis for the multilayer structure is developed and an original feeding system is designed and optimized to provide the needed wideband impedance matching. Thanks to translational invariance enabled by the homogenized nature of the partially reflecting screen, the antenna is used as a radiating element in the design of a leaky-wave-enhanced phased array, constituted by an arrangement of vertical probes to generate directive pencil beams steerable at a single frequency in azimuth and by changing frequency in elevation.