Coil and Magnet Design for Nuclear Magnetic Resonance in Inhomogeneous Field

High-resolution nuclear magnetic resonance (NMR) spectrometry is possible in nonhomogeneous magnetic fields-such as those in portable equipment-if the static and the radio-frequency (RF) magnetic fields are perpendicular and correlated in the measurement volume. From the easy-axis rotation theorem and the Amperian currents model, it is possible to exactly match two magnetic fields in two-dimensional systems. We derive a basic probe element that fulfills these conditions. Then we present a portable NMR probe design. The static and RF magnetic fields of the probe are matched on a large volume