MAGNETIC RESONANCE IMAGING SYSTEM WITH A CLASS-E RADIO FREQUENCY AMPLIFIER

摘要

A Class-E amplifier has bee adapted for use in the radio frequency section of a magnetic resonance imaging (MRI) system. A drive signal is produces by modulating the envelope of a radio frequency carrier signal and then applied to a switch in the Class-E amplifier. The switch is connected in series with a choke between a supply voltage terminal and circuit ground with an output node formed between the choke and the switch. The output node is coupled to circuit ground by a shunt capacitor. In a preferred embodiment, a pair of such amplifiers, that are II radians out of phase, are connected to each rung of a transverse electromagnetic transmit array type radio frequency coil of the MRI system.