Hybridized eigenmodes of periodic wire arrays and their application in radiofrequency coils for preclinical MRI

Abstract

In this contribution we discuss the application of periodic structures composed of resonant metal strips in radio-frequency coils for preclinical multi-nuclei magnetic resonance imaging (MRI). For these multi-wire structures we numerically demonstrate a variety of hybridized eigenmodes calculating their magnetic field patterns and discuss their selective excitation. We show that by properly exciting two particular eigenmodes with a small non-resonant loop feed one can construct a dual-frequency coil for MRI. The field of view of the coil at both frequencies is determined by the magnetic field patterns of the selected modes, as shown by full-wave numerical simulations. The choice of the excited eigenmodes determines the field penetration depths into a scanned subject at the corresponding resonant frequencies. Moreover, in this work we discuss miniaturization of multi-wire resonators by capacitive loading of strips.