Abstract: Disclosed is a novel two-way duplexer structure for the simultaneous transmission and reception of circularly polarized microwaves. This two-way duplexer of the type designed to connect a first set of two inputs/outputs to a second opposite set of two inputs/outputs, each input/output of said duplexer being connected to the combination channel of a combiner/divider, the two division channels of each combiner/divider each providing for the connection with one of the division channels of one of the combiners/dividers connected to a distinct input/output of the opposite set of inputs/outputs, through distinct phase-shifting means.