A single-chip integrated transceiver for high field NMR magnetometry

We present the design and performance of a broad-band single-chip integrated transceiver specifically conceived for nuclear magnetic resonance magnetometry. The single-chip transceiver is realized using a standard silicon complementary metal-oxide-semiconductor integrated circuit technology. A radio-frequency (RF) transmit amplifier, a transmit/receive switch, a low noise RF receive amplifier, a quadrature (IQ)-mixer, and two intermediate frequency amplifiers are integrated on a single silicon chip of 1.8 mm². The advantages and problematic aspects with respect to conventional discrete electronic approaches are discussed. We show the results of magnetic field measurements performed at 1.4 and 7.05 T, using solid and liquid samples having volumes from 40 μl down to 100 pl. Particular attention is devoted to the comparison of the experimentally measured magnetic field standard deviation with respect to the Cramer-Rao lower bound value. With a sample of distilled water (T₁ ≅ T₂ ≅ 3 s, $T2*≅$ 20 ms) having a volume of 40 μl, a standard deviation of 2.5 nT at 7.05 T (i.e., 0.5 ppb) in 1 s of averaging time is achieved, with a projected Cramer-Rao lower bond of 8 pT (i.e., 1.1 ppt).