Reconfigurable packaged GaN power amplifier using thin-film BST varactors

A compact and reconfigurable GaN HEMT power amplifier using thin-film BST varactors, mounted inside a customized RF package is presented. With tuning of input and output matching networks several advanced functionalities, e.g. efficient back-off operation, frequency agility, VSWR protection, and post tuning of mismatched loads can be realized. Two prototypes were manufactured and measured on a probe station and in a microstrip test fixture. The amplifier was characterized for varactor tuning voltages up to 24 V and delivered a maximum output power of 37.4 dBm and 58% PAE. Furthermore, the linearity of the amplifier under various tuning states was characterized by two-tone measurements. It shows no additional intermodulation compared to a bare GaN HEMT.