ABSTRACT
Radio frequency (RF) transistors are devices able to amplify high-frequency signals. A key feature of any transistor is its ability to amplify currents, voltages, and powers. The Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is operated in common-source configuration. This is the typical operating mode of RF MOSFETs and is comparable to the common-emitter configuration of bipolar transistors. Among the RF transistor figures of merit, the cutoff frequency fT and the maximum frequency of oscillation fmax are probably the most important ones. In order to construct useful RF circuits, the transistors used in these circuits must possess a certain level of fT and fmax. The minimum noise figure NFmin is important for RF transistors used in low-noise amplifiers. The output power Pout and the power-added efficiency PAE are two figures of merit relevant to RF power transistors. Valuable insights into the high-frequency performance of RF MOSFETs can be obtained from analyzing the small-signal equivalent circuit.
