A 20W 2-20 GHz GaN MMIC Power Amplifier Using a Decade Bandwidth Transformer-Based Power Combiner

This paper presents the design and measurement of a two-stage, 2 - 20 GHz GaN MMIC power amplifier fabricated on 100 µm silicon carbide using Qorvo's QGaN15 released process. A two-stage non-uniform distributed power amplifier having decade bandwidth is implemented as the core amplifier to achieve high power and PAE. Two of the core amplifiers are combined in parallel using a decade bandwidth on-chip transformer-based power combiner which enables the output power over the 2–20 GHz band to be significantly increased relative to current state of the art. The MMIC power amplifier is fully integrated, having on-chip DC blocking capacitors at the RF terminals and on-chip RF bias inductors while only requiring low-cost bypass capacitors at the power supply terminals. The measured PA produces 42.6 - 44.9 dBm of CW output power over the 2 - 20 GHz band with 18.0 - 29.7 % PAE using a 22 V supply voltage. The large signal gain varies between 11.6 and 13.9 dB. The design is realized in 25.8 mm 2 resulting in a power density of 0.7 -1.2 W/mm 2 over the full bandwidth.