High Efficiency and High Gain GaN HEMT Power Amplifiers for 5G-Connected Cars and SATCOM applications

1.1 Background: In recent years, the evolution of wireless communication systems has driven a growing needfor highly efficient RF power amplifiers (PAs). This trend is primarily associated with thedevelopment of fifth-generation (5G) networks and the widespread diffusion of Internet ofThings (IoT) technologies [1]. As 5G infrastructures continue to expand and IoT devicesbecome increasingly pervasive, the performance requirements imposed on RF front-endarchitectures have become significantly more demanding. Beyond conventional smartphoneapplications, these technologies are progressively being integrated into more complex andhigh-reliability scenarios, including automotive connectivity and satellite communicationplatforms [2][3]. Such applications typically operate in the microwave frequency range,where efficient exploitation of the available spectrum is essential to sustain the multi-gigabitdata rates envisioned for next-generation communication systems [4]. Under these conditions,the power amplifier represents a critical subsystem, as it must simultaneously deliver elevatedoutput power levels and maintain high efficiency across a broad operational bandwidth [5].Achieving this combination of performance metrics constitutes one of the main technologicalchallenges in modern RF power amplifier design.For instance, the heat produced when the amplifier operates at high output power levelsmay induce significant thermal stress, potentially deteriorating the device reliability andoverall performance. For this reason, proper thermal management strategies and an accuratedesign methodology are essential [6]. In addition, power amplifiers exhibiting higher poweradded efficiency (PAE) reduce the burden on cooling systems, since a larger fraction of thesupplied DC power is effectively converted into useful RF output power [7]. Furthermore,the intrinsic nonlinear behavior of active devices contributes to efficiency degradation, asharmonic components generated during operation draw additional power and introduce signaldistortion. Properly balancing efficiency, linearity, and thermal constraints is therefore a keychallenge in the development of high-performance microwave power amplifiers. The firstpart of this work addresses the design of a two-stage 20 W GaN power amplifier operatingin the L/S band, specifically intended for 5G automotive connectivity in the frequency rangebetween 1.9 and 2.3 GHz [8]. The second part instead focuses on the design of a 7 W GaNHEMT power amplifier for satellite communication (Satcom) applications in the K-band.