| 摘要 |
Impedance matching between the RF probe and the spectrometer is a standard requirement for NMR probes. Both lumped element and branched transmission line methods are in wide use. Here we propose to use a segmented transmission line structure. It relies upon reflections between transmission lines of different impedances that are serially connected to match the impedance of a coil or resonator to the characteristic impedance of the NMR spectrometer. In an embodiment, two quarter-wave length dielectric slugs are placed within a coaxial transmission line. Adjustment of the positions of the slugs allows the variable tuning and matching needed for NMR probes, eliminating the need for variable capacitors and inductors.
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