A New Low Loss Rotman Lens Design for Multibeam Phased Arrays

The design methodology and analysis of a new low loss Rotman lens beam-forming network is presented. With the introduction of dielectric contours of varying permittivity within the lens, enhanced focusing is achieved. The varying permittivity is realized through a synthesized dielectric technique, where a periodic lattice of holes is formed within the dielectric substrate. In comparison to a conventional Rotman lens of similar shape and size, this new enhanced focused Rotman lens shows an insertion loss improvement of 1.2 to 2.0 dB. Also, the decrease in gain at the extreme scan angles is reduced from 1.5dB to 0.7dB