Optimum Remote Tuning/Matching NMR Probe Achieved with a Suitable Transmission Line Length and a Suitable Local Tuning/Matching Circuit

In many nuclear magnetic resonance (NMR) applications, the receiving coil must be as close as possible to the region of interest (ROI) and this limits the access in situ to the settings of local tuning and matching capacities. Here, we develop a method showing that according to the work frequency there is a suitable transmission line length and according to the features of the coil there is a suitable local tuning/matching circuit configuration to insert between the coil and the transmission line. The simulation method has been applied on two different coils models and correlated by results obtained on test bench. The resulting bandwidth, about 30 MHz, makes settings more comfortable and opens the possibility for tuning at different nuclei with very close resonant frequencies.