Radiofrequency Resonator Design

The inductively coupled solenoidal radiofrequency resonator design. (A) Circuit diagram of the resonator showing the five individual resonant loops coupled via mutual inductance and driven with an inductively coupled drive loop. Capacitor values were as follows: C=62 pF, C1=30 pF, C2=30 pF and Cv=5-40 pF. Adjustment of the distance between the drive loop and the resonator facilitated matching of the resonator with the 50-ohm; transmission line leading to the RF transmitter and receiver (not shown). (B) A fixed specimen of the murine brain and sketch of the resonator showing the positions of the capacitors, drive loop and transmission line. (C) The resonant mode spectrum of the five-element resonator. The five discrete modes predicted from the dispersion relation are visible, but only the lowest in frequency produces a field profile with all elements oscillating in phase and therefore most suitable for imaging.