Michael Twieg1, Soumyajit Mandal1, and Mark A Griswold1,2
1Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, United States, 2Radiology, Case Western Reserve University, Cleveland, OH, United States
Dense MRI receiver arrays
face challenges associated with RF cabling, power consumption, and space
required by on-coil RF LNAs. On-coil frequency mixers and ADCs have been
proposed as solutions to these challenges. Here we propose the use of passive
N-path mixers implemented in CMOS for on-coil frequency conversion. We
demonstrate a prototype fabricated in a 0.5µm CMOS process, and compare its
measured and simulated performance. We also show simulations of a similar
design in 65nm CMOS with greatly improved performance. The improved version may
handle multiple RF channels on a single chip, and eliminates the need for RF
LNAs entirely.
