Active Detuning of MRI Receive Coils with GaN FETs

Abstract

Here, we present the use of Gallium Nitride (GaN) FETs as a replacement for PIN diodes in active detuning circuits for magnetic resonance imaging (MRI) receive coils at 63.6 MHz. We use simulated circuit models, benchtop measurements, and imaging experiments to show that GaN FETs perform comparably with a common MRI-compatible PIN diode. The GaN FET-based circuits require orders of magnitude less bias current to operate, effectively eliminating ${\rm B}_{0}$ distortion resulting from biasing.