Several services associated with satellite on the move and 5G applications are populating the K and Ka frequency bands. Beam forming networks are crucial components for achieving the necessary beam flexibility and agility of these systems. The Rotman lens is being widely investigate as a cost-effective solution for overcoming the main limitations of other types of beam forming networks, namely bandwidth, complexity, and size. One of the main design challenges is obtaining broadband transitions for the array and beam ports. In this work, we used a standard K/Ka double ridge (WRD180) for interfacing with the Rotman Lens. The main motivation for this choice is the wide bandwidth, compatible with the K/Ka satcom frequency bands, and the use of air/vacuum propagation medium in the parallel plate waveguide section to avoid dielectric losses associated with microstrip implementations. We present a design capable of fully exploiting the ridge waveguide bandwidth with wide beam scanning, outperforming previous works. The presented design consists of a 13×7 Rotman Lens with a scanning range of ±50 degrees operating between 16 and 40 GHz, validated through full-wave simulations.

In this work an all-metal Rotman lens antenna design is presented. Ridge waveguides are used for the input and output ports of the lens to achieve broadband behavior in the K/KA bands of the new generation of satellite communications (17 GHz to 30 GHz). The Rotman lens is composed by 5 input and 5 outputs ports, with a maximum beam scanning of 30 degrees. The connection between the input and output ports is done through a parallel plate waveguide (PPW) in the TEM regime. This simple configuration allows to have an initial assessment of the antenna port isolation and return losses, for the designed ridge to parallel plate waveguide transitions. This preliminary work shows promising results which pave the way for future improvements in terms of bandwidth and scanning performance.