On the design of an active circulator

Design of a fully monolithically integrable active circulator without any externally added circuit components is described in this paper. Two different configurations for active circulators using power dividers and Lange couplers are investigated. The circuit using Lange couplers indicates superior performance and is capable of providing O‐dB loss and return loss and isolation better than 16 dB and 23 dB, respectively, over an octave or higher bandwidth.