The network analysis of chiral cascaded circuit and its novel application on directional coupler

We theoretically investigate the four-port network parameters of chiral cascaded circuit and present a new approach to realizing compact directional coupler based on it. This novel coupler characterizes good isolation. Besides, its coupling coefficient can be easily designed by tuning the turns ratio of transformers and its operating frequency can be additionally designed by tuning the series inductance and parallel capacitance. A prototype of 20dB-coupler is proposed to show the design procedure of chiral cascaded circuit-based coupler, which is validated by Aglient’s ADS simulation.