A Symmetric Coupled Line Equivalent Circuit Model for Asymmetric Coupled Lines

摘要

A new equivalent circuit model is proposed for an asymmetric coupled linernbased on a symmetric coupled line. The proposed equivalent circuit consists of a symmetricrncoupled line and two ideal transformers to represent an asymmetric coupled line and can berneasily incorporated into the existing microwave and RF circuit simulators. This makes it easierrnto model and simulate the asymmetric coupled line circuits in terms of simple symmetricrncoupled lines. Using the proposed equivalent circuit model, it is shown that an asymmetricrncoupled line coupler is electrically equivalent to a symmetric coupled line coupler with transformedrnport impedances and the relation between the two couplers is investigated throughrnthe established equivalence. The validity of the proposed model is confirmed through thernanalysis of the directional couplers and the impedance transformers involving the asymmetricrncoupled lines.