Evaluation on Coupling Strategies for Ultra-high Field Mri Probe Made of Cylindrical Dielectric Resonator

Open Access
Author:
Liu, Rui
Area of Honors:
Interdisciplinary in Electrical Engineering and Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Michael T Lanagan, Thesis Supervisor
  • Michael T Lanagan, Honors Advisor
  • Jeffrey Scott Mayer, Honors Advisor
  • Steven Edward Perini, Faculty Reader
Keywords:
  • Ceramic dielectric resonator
  • 14 Tesla MRI
  • coupling method
  • power transmission
  • Q value
Abstract:
Research into the properties of ceramic dielectric resonators (CDR) showed potential applications in magnetic resonance imaging (MRI). Replacing traditional radiofrequency (RF) coils in current design with ceramic dielectric resonators would improve signal-to-noise ratio (SNR) and spectral resolution that render an enhanced imaging quality. The objective of this research project is to investigate alternative coupling methods and probe designs to achieve ideal resonance frequency and power transmission for optimized performance. Specifically, Network Analyzer was utilized for investigating different coupling configurations targeting 14 Tesla pre-clinical MRI machines. Several coupling methods were investigated: a full loop around the resonator (previous work), a double loop around the resonator, a triple loop around the resonator and a quadruple loop around the resonator. The result showed that by implementing a triple loop around the resonator, the effective power transmission was increased by 157% to -10.656 dB compared to previous design. Further, with modified copper tuning pieces, the resonant frequency could be tuned down to the operating frequency of 600 MHz, which solved the previous problem of a minimum resonant frequency of 605 MHz. The current triple loop prototype design turned out to be the best coupling configuration with relative high power transmission, low SNR and a tunable frequency range covering 600 MHz.