Zens, Albert P. “Using Magnetic Coupling to Improve Multiple Resonance NMR Probe Circuits.” Journal of Magnetic Resonance 316 (July 2020): 106741.
https://doi.org/10.1016/j.jmr.2020.106741.
Multiple resonant NMR circuits are an especially important aspect of modern NMR detectors. Today NMR researchers can carry out direct observe, indirect observe and double or triple resonance experiments on many different nuclides without having to change the NMR probe. The price for this convenience is loss in efficiency. In this paper it is explained how by using magnetic coupling and symmetric multiple resonance circuits the efficiency of these experiments can be improved over capacitively coupled circuits to 50 Ω ports.