Broadband 100-W Ka-Band SSPA Based on GaN Power Amplifiers

• Published in: IEEE microwave and wireless components letters Vol. 32; no. 6; pp. 708 - 711
• Main Authors: Neininger, Philipp, John, L., Zink, M., Meder, D., Kuri, M., Tessmann, A., Friesicke, C., Mikulla, M., Quay, R., Zwick, Thomas
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2022
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Ka -band; Broadband communication; Gain; Gallium nitride; HEMTs; Microwave circuits; power combining; Power generation; Power measurement; solid-state power amplifier (SSPA); waveguide
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2022.3166563

In this letter, we report on the realization of a two-stage 16-way solid-state power amplifier (SSPA) in the Ka -band. To this end, we describe the design of a high-power amplifier (HPA) in a 100-nm gallium nitride (GaN) process and its integration into a split-block waveguide module. The PA module achieves an output power of more than 7.6 W between 28 and 39 GHz. In conjunction with 16 of these PA modules, we then employed a custom low-loss radial splitter and combiner to create a compact SSPA system. The two-stage SSPA configuration exhibits a small-signal gain of up to 44 dB and a peak output power of 127 W at 31 GHz in 5 dB of gain compression. Furthermore, we measured output power of close to 100 W and state-of-the-art efficiency values of more than 19% between 28 and 38 GHz. To our knowledge, this is the most broadband high-power SSPA demonstrated so far in this frequency range.