Probe efficiency improvement with remote and transmission line tuning and matching

Abstract

In certain nuclear magnetic resonance (NMR) applications in which accessibility to the gantry is limited, performing optimal tuning and matching represents a major problem. Here, we discuss a method of tuning NMR probe circuits and matching their impedances which uses cables with different impedance values. This simple but efficien method may be advantageous compared with much more difficul perfect tuning and matching.

Determining the tuning and matching requirements of RF coils using electromagnetic simulation and electric circuit analysis

“…Tuning is usually performed using variable capacitors in association with the fixed inductance and fixed capacitance of the RF coil, although variable geometry schemes with variable inductance and/or capacitance have also been used (1)(2)(3). Matching is usually performed using simple lumped-element capacitive and/or inductive matching schemes, although transmission-line schemes are possible (4 ). Generally, tuning and matching are interactive, and therefore successive adjustments to both the tuning and matching circuits are required for optimal coil performance.…”