PIN diode driver for NMR and MRI

• Published in: Journal of magnetic resonance (1997) Vol. 300; pp. 114 - 119
• Main Authors: Johansen, D.H., Albannay, M.M., Petersen, J.R., Zhurbenko, V., Ardenkjær-Larsen, J.H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2019
• Subjects: Active decoupling; Driver; MRI; NMR; PIN diode; Q-spoiling; Switch; TR switching; Q-spoiling; NMR; Active decoupling; Switch; MRI; Driver; TR switching; PIN diode
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2019.01.017

[Display omitted] •A PIN diode driver with current limiting for the transmit state was constructed.•The driver switches from transmit to receive in 0.4 μs and from receive to transmit in 2 μs.•Enabling custom transmit-receive and Q-spoiling switching based in PIN diodes.•The driver is based on readily available components.•Equal SNR performance is achieved compared to commercial solutions (NMR spectrometer and MRI scanner). Designing custom coils for magnetic resonance systems, such as nuclear magnetic resonance (NMR) spectrometers and magnetic resonance imaging (MRI) scanners, often entails using non-standard configurations of the transmit-receive (T/R) switch and Q-spoiling circuits. The built-in drivers of commercial NMR and MRI systems are, typically, only reconfigurable within a narrow application range (if at all). Thus, the built-in driver may not be able to properly control the custom T/R switches and Q-spoiling circuits when using custom built coils. We present a PIN diode driver which functions in both an MRI scanner and NMR spectrometer. The PIN diode driver is based on readily available discrete components and achieves switching times for the reverse and forward bias states (transmit on and off) of 2 μs and 0.4 μs respectively. Hence, this work enables a higher degree of customization of the RF switching circuits in an MR system and is potentially of interest for designers of custom coils for both NMR spectrometers and MRI scanners.