8kW Non-magnetic RF Power Amplifier of 5T Human Body Magnetic Resonance

The ultra-high field magnetic resonance imaging (MRI) system has become a key focus of clinical and scientific research due to its remarkable sensitivity and resolution. However, achieving whole-body MRI at ultra-high field strengths necessitates enhanced power-drive capability in order to optimize the excitation of radio frequency (RF) coils. To avoid significant signal transmission losses, it is necessary to ensure that the RF transmission chain has a high transmission efficiency. An 8 kW non-magnetic RF power amplifier (RFPA) has been proposed for 5T whole-body magnetic resonance imaging. The proposed non-magnetic structure allows the RF power amplifier to be placed directly in the scanning room, thereby reducing transmission distance and enhancing transmission efficiency. The multi-stage amplification structure based on high power MOSFETs employed a magnetic-planar balun and a lumped-distributed power combiner design to attain a peak output power of 8 kW (69 dBm). Additionally, The nonlinearity correction of gain and status monitoring of the amplifier was facilitated by incorporating a dual directional coupler and feedback control loop design.