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 .PI. radians out of
phase, are connected to each rung of a transverse electromagnetic
transmit array type radio frequency coil of the MRI system.