According to one aspect, a nuclear magnetic resonance (NMR)
radio-frequency (RF) coil of an NMR spectrometer includes
oppositely-facing arches at opposite longitudinal ends of the coil
window, along shielded regions of the coil. The arched coil shapes allow
situating the transverse parts of the coil away from the interfaces
between the sample measurement volume and coil shields while minimizing
the additional coil length and thus coil inductance and capacitance
needed to move the transverse conductors away from interfaces. Moving the
transverse parts of the coil away from the measurement volume facilitates
shimming. The coil may be lifted on a plurality of longitudinal support
rods spaced around a circumference of the coil, in order to reduce the
capacitance between the coil and associated shields.