Abstract
A wideband design model for 4×4 microstrip Rotman lens is presented, with a precise behavior of return loss of the ports and their phase centers. The procedure for choosing the optimum geometrical parameters of lens and modifying the curvature of sidewalls yield a very wideband lens. Based on the presented model, a prototype has been built for the true time delay phasing of an antenna array for the frequency range from 8GHz to 26GHz. The fabricated 4×4 Rotman lens has an average amplitude error of 0.5dB and phase errors of 2 degree. All the beams have a fixed position in frequency band and the maximum deviation of the beams from the ideal position is less than 0.65 degree.
