Waveguide-type Transmitarray Antennas with a Concave Surface Profile Analogous to Rotman Lens for Spatial Feeding to Radiate Collinear Multi-Beams

This paper presents an architecture of transmitarray antenna consisting of waveguide-type elements. The array has a planar surface profile facing the beam directions of radiation, and has a convex surface profile facing to the feeds of illumination. The concave surface is analogous to the curve of Rottman lens for the applications of multi-beam radiation. The additional phases required in the concept of Rotman lens are created by controlling the domensions of waveguides. The transmitarray becomes very compact and functions in a standing alone fashion when it is illuminated by multiple feeds. The algorithm and examples will he demonstrated by numerical examples.