Design of Rotman Lens with Non-uniform Beam Port Distribution

A new design of Rotman lens with non-uniform beam port distribution is presented in this letter. The genetic algorithm is adopted to optimize the quality of beam coverage. Compared with conventional Rotman lens with uniform beam port distribution, the proposed design can cover a given scan range with fewer beams. i.e., fewer RF channels. Consequently, the cost and complexity of the antenna system is reduced. A microstrip Rotman lens with a scanning range of ±45o over 8-12 GHz has been designed and simulated to verify the proposed idea. The simulated results show that only 25 beams can achieve less than 3 dB overlapping level of the adjacent beams and less than 13 dB overlapping level of every other beam. By contrast, at least 28 beams are required for the uniform case.