Compact novel CPW ferrite coupled line circulator with left-handed power divider/combiner

TLDR: In this paper, a three-port coplanar waveguide (CPW) ferrite coupled line (FCL) circulator is presented for the first time, which is designed as a cascade of a CPW section of FCL and a left-handed T junction.

Abstract: A novel three-port coplanar waveguide (CPW) ferrite coupled line (FCL) circulator is presented for the first time. The circulator is designed as a cascade of a CPW section of FCL and a left handed T junction. The FCL section is an axially-magnetized and it requires no external DC magnetic bias on operation. Also, left-handed T junction power divider/combiner has the advantages of its broadband and compact size (50% size reduction at the mid frequency compared to conventional T junction) at the same time. The results show that the novel CPW circulator demonstrates obvious power circulation with small insertion loss, high return loss, and high isolation. The proposed circulator has broad bandwidth from 8 GHz to 12 GHz (40 % fractional bandwidth). The average insertion loss is almost 3 dB whereas the return loss and the circulation isolation in all cases are better than 10 dB.