A Direct Conversion Transceiver for Portable Microfluidic NMR Flowmeters
E. Aydin (TU Delft - Electronic Instrumentation)
A. Jouyaeian (TU Delft - Electronic Instrumentation)
Zhong Tang (TU Delft - Electronic Instrumentation)
K.A.A Kofi (TU Delft - Microelectronics)
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Abstract
This paper presents a direct conversion transceiver intended for use in a microfluidic NMR flowmeter. It consists of an H-bridge power amplifier, which drives a hand-wound milimeter-sized coil with RF signals, and a direct conversion receiver, which amplifies the NMR signals picked up by the coil, and then digitizes them with an asynchronous 8 bit SAR ADC sampling at 70 MHz. Fabricated in a 65 nm CMOS technology, the receiver achieves a noise spectral density of 1 nV/sqrt(Hz) at 21 MHz, while dissipating only 36 mW. A microfluidic flowmeter based on the transceiver and a handheld 0.5 T permanent magnet can measure flow rates up to 96 ml/h in a 0.8 mm inner-diameter channel with pm 1.3 % full-scale error. To the authors' best knowledge, this is the first reported portable NMR flowmeter.