Fully-Integrated Non-Magnetic 180nm SOI Circulator with > 1W P1dB, >+50dBm IIP3 and High Isolation Across 1.85 VSWR

There has been recent progress on CMOS non-magnetic circulators based on switch-based spatio-temporal conductivity modulation, but these initial demonstrations remain limited in transmitter power handling, linearity, and ability to combat antenna variations. This paper describes a non-magnetic circulator in 180nm SOI CMOS that uses no external components, and employs various linearity enhancement techniques such as device stacking, optimal switch biasing, and localized ESD design to achieve >1W TX-ANT PldB and >+50dBm TX-ANT IIP3 at 1GHz. A new loss-free and inductor-free antenna balancing approach enables high isolation for as high as 1.85 ANT VSWR and beyond. The circulator also exhibits low insertion losses of 2.1dB/2.9dB in the TX-ANT and ANT-RX paths, and ANT-RX NF of 3.1dB. These results represent a 10–100×enhancement in linearity/power handling over prior CMOS non-reciprocal circulators, and are shown to lower the power consumption of a communication link when compared with state-of-the-art electrical balance duplexers in scenarios where dynamic range is limited by P1dB, NF.