Planar Trifocal Mirror–Lens Slotted Waveguide Antenna Array

A planar trifocal slotted waveguide antenna array is proposed and investigated. The antenna contains two layers the first of which is a planar waveguide with a dielectric lens and the second layer is an array of dielectric-filled rectangular metal waveguides with slots on wide walls. The layer coupling is provided by a curvilinear slot in a common wall, and the layers are closed on one side by a curved mirror adjacent to the lens surface. A solution to the synthesis problem is used to determine the surfaces of the lens and the slot positions in rectangular waveguides that allow radiation of a plane wave at three positions of the source of a cylindrical wave (feed) in the planar waveguide. The rms aberration is studied for an antenna array optimized for angles of view of 40 and 80 degrees when moving the feed along the focal curve, and the results are compared with aberrations in bifocal and trifocal arrays with mirror focusing systems.