2016 The Royal Society of Chemistry. The RF power amplifier is one of the major sub-units in the MR transmit chain. Solid-state devices form the core of modern amplifiers. In this chapter, the basics of MOSFET-based power amplification are first introduced. An examination of the different classes of amplifiers shows some of the fundamental trade-offs in amplifier design. From there the basics of matching networks are covered, followed by a brief review of performance metrics for amplifiers used in MR. The final sections look at advanced designs specifically aimed at amplifiers used for transmit arrays.
