Direct matching methods for coils and preamplifiers in MRI

• Published in: Journal of magnetic resonance (1997) 2018-05, Vol.290, p.85-91
• Main Authors: Cao, Xueming, Fischer, Elmar, Hennig, Jürgen, Zaitsev, Maxim
• Format: Article
• Language: English
• Subjects: Low noise; Matching network; Preamplifier; Receiver coil
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2018.03.009

[Display omitted] •Direct matching methods for coils and preamplifiers in receiver arrays.•The reactance of the input impedance of preamplifiers is used to decouple the coils.•The coil loop can be matched to the transistor in the preamplifier directly.•The new matching networks have fewer noise than the conventional method. In this paper, direct matching methods for coils and preamplifiers in receiver arrays are presented. Instead of compensating the reactance of the input impedance of preamplifiers, in our method, the reactance was used to resonate with the coil matching networks and thus to decouple the coils. Furthermore, coil matching networks and preamplifier input matching networks were combined, meaning the coil loop can be matched to the transistor in the preamplifier directly. These matching methods and, for comparison, the conventional matching method were implemented with custom-made preamplifiers and coils. Decoupling and noise-matching performance were compared between these three configurations. Phase shifting networks between coils and preamplifiers are not necessary in our matching methods. With fewer components, these matching networks showed lower noise factors, while similar preamplifier-decoupling performance was found for all three methods.