Microstrip Rotman lens fed array using multisection transition

The Rotman lens is a multi-input device which controls the beam scan angle, depending on the phase shift corresponding to the path length between the input source positions and the radiator elements. The matching between the transmission lines and the parallel plate region of the lens is one of the important factors of the performance of a Rotman lens built on a microstrip. A matching method is suggested and applied between the center feed line and the parallel plate region of the lens. The return loss show a very good matching between the feed line and the microstrip Rotman lens.