RF/microwave power amplifiers (PAs) dissipate power, which leads to a rise in operating temperatures that can extend from the single IC stage to an entire, highly integrated RF system. Higher temperatures degrade both the immediate and long-term performance of RF electronics.
Such temperatures are directly linked to reduced device lifetime or mean-time-to-failure (MTTF) for metal semiconductor field-effect transistor (MESFET), pseudomorphic high-electron mobility transistor (pHEMT), and heterojunction bipolar transistor (HBT) devices used in gallium-arsenide/gallium-nitride (GaAs/GaN) monolithic microwave ICs (MMICs). Reliability and MTTF are of special concern for harsh environments and applications that are hard to service, such as remote base stations and satellite communications.