Figure 4
From: Non-magnetic four-port electronic circulators based on \(90^\circ \) non-reciprocal phase-shifters
Sub-circuits of four-port circulators: (a) four-port presentation and analysis of the \(90^\circ \) NRPS. (b) standard quadrature-hybrid four-arm distributed realization. c distributed realization of the modified quadrature-hybrids with four equal \(90^\circ \) (\(\lambda /4\)) \(Z_0\) arms.
