Flexible-Resolution, Arbitrary-Input, and Tunable Rotman Lens Spectrum Decomposer

We present an enhanced design - in terms of resolution flexibility, input port position arbitrariness, and frequency range and resolution tunability - of the planar Rotman lens spectrum decomposer (RL-SD). The resolution flexibility enhancement consists in allowing different frequency sampling functions (decreasing, uniform, and increasing) by properly distributing the output port locations along the frequency-position law of the RL-SD. The input port position arbitrariness is realized by adding a calibration array compensating for the frequency deviation induced by the input modification. The frequency range and resolution tunability is achieved by electronic port switching. A complete design procedure is provided and two enhanced RL-SD prototypes, with uniform port distribution and uniform frequency resolution, respectively, are numerically and experimentally demonstrated.