A Wideband Active Quasi-Circulator With 34-dB Isolation and Insertion Loss of 2.5 dB

Abstract

Based on the dual-path cancellation methodology, a noise cancellation technique and an insertion loss (IL) mitigation technique are presented to improve the properties of the active quasi-circulators. The proposed circulator is fabricated with a standard 0.18-μm CMOS process, occupying an area of 0.91 mm × 0.49 mm including the pads. The measurement results show that 34-dB isolation is obtained over a wide frequency range from 1 to 8 GHz, while the IL is below 2.5 dB and the noise figure (NF) is less than 10 dB.