Capacitively decoupled tunable loop microstrip (TLM) array at 7 T

Magn Reson Imaging. 2007 Apr;25(3):418-24. doi: 10.1016/j.mri.2006.09.031. Epub 2006 Nov 22.

Abstract

Microstrip transmission-line loop arrays have been recently proposed for parallel imaging at ultrahigh fields due to their advantages in element decoupling and to their increased coil quality factor. In the microstrip loop array design, interconnecting capacitors become necessary to further improve the decoupling between the adjacent elements when nonoverlapped loops are placed densely. However, at ultrahigh fields, the capacitance required for sufficient decoupling is very small. Hence, the isolations between the elements are usually not optimized and the array is extremely sensitive to the load. In this study, a theoretical model is developed to analyze the capacitive decoupling circuit. Then, a novel tunable loop microstrip (TLM) array that can accommodate capacitive decoupling more easily at ultrahigh fields is proposed. As an example, a four-element TLM array is constructed at 7 T. In this array, the decoupling capacitance is increased to a more reasonable value. Isolation between the adjacent elements is better than -37 dB with the load. The performance of this TLM array is also demonstrated by MRI experiments.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electric Capacitance
  • Equipment Design
  • Equipment Failure Analysis
  • Image Enhancement / instrumentation*
  • Image Enhancement / methods
  • Magnetic Resonance Imaging / instrumentation*
  • Magnetic Resonance Imaging / methods
  • Magnetics / instrumentation*
  • Phantoms, Imaging
  • Transducers*