Integrated retrodirective/beam-switching phased array using dual-mode left-handed synthesized transmission lines

Without the need of active switches, a heterogeneous integrated retrodirective/beam-switching phased array is proposed in this paper. Its topology is complementary to the one we proposed in the literature. With left-handed synthesized transmission lines in microstrip form, the current version can behave identical to a reflection-type retrodirective array in the lower band, but automatically turns into a beam-switching array using the Butler matrix in the upper band. Together with the previous design, a real interrogator-transponder system can be realized. The design concept and experimental results will be introduced.