Journal
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
Volume 68, Issue 12, Pages 5168-5181Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TCSI.2021.3113187
Keywords
Impedance; Interference cancellation; Transmission line matrix methods; Scattering parameters; Circulators; Silicon carbide; Radio frequency; Full-Duplex (FD); electrical balanced duplexer (EBD); electronic-circulator (EC); self-interference cancellation (SIC); load balancer (LB); non-reciprocal phase shifter (NRPS); impedance transparency
Categories
Ask authors/readers for more resources
This article introduces a new electronic device - the four-port quasi-circulating quadrature hybrid (QCQH), combining characteristics of electronic circulators and quadrature hybrids. Various design alternatives, including a 90 degrees transmission line and lumped transformer, are discussed for the QCQH based on a two-port N-path circuit. Experimental results show good TX isolation and transmission performance at different frequencies, along with impressive TX EVM results.
This article presents a new electronic device - the four-port quasi-circulating quadrature hybrid (QCQH), which combines desirable features of electronic circulators and quadrature hybrids. The QCQH comprises three quarter-wavelength transmission lines and a 90 degrees non-reciprocal phase shifter (NRPS) and is suitable for inband full duplex applications. We derive the four-port S-parameter matrix of the QCQH and the transfer functions under termination scenarios of interest. The resulting closed-form expressions are compared with the prior art electronic circulator. A 90 degrees transmission line and lumped transformer alternatives are considered for designing a QCQH based on a two-port N-path circuit. TX isolation and transmission expressions are derived and verified against simulations, and a new wideband leakage cancellation approach is proposed. A TSMC 65 nm CMOS N-path chip is integrated on-board with a discrete, lumped, LCL transformer implementation. TX-to-antenna insertion loss of 1.4 dB and an RX NF of 4.7 dB at the frequency of 1 GHz were measured with a primary passive TX-RX isolation of 21 dB. Total isolation of more than 50 dB for an 80 MHz OFDM WiFi TX signal employing digitally equalized active leakage cancellation was achieved along with better than -40 dB TX EVM with SIC ON.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available