# Broadband Millimeter-Wave 5G Power Amplifier Design in 22 nm CMOS FD-SOI and 40 nm GaN HEMT
## 5 Conclusions  
This work presented three different, very broadband, linear, and efficient PAs that can operate over the entire key mm-Wave 5G FR2 band of 24-44 GHz in two different state-of-the-art semiconductor IC technologies. Using a third-order input-matching network, a broadband, single-ended 40 nm GaN PA was designed (i.e., GaN PA #1), achieving excellent performance from 18 to 44 GHz, with the highest measurement maximum PAE/\(P_{OUT,SAT}\) of 42.1%/18.6 dBm at 28 GHz at \(V_{DD}\) = 4 V. Small-signal and large-signal CW measurement data matched EM PEX simulations well, with maximum PAE above \(\sim\)20% across the entire frequency band. When inserting a 256-QAM 5G NR signal varying in BW from 50 MHz to 9 \(\times\) 100 MHz at 24, 28, 37, and 39 GHz, there is virtually no degradation in the linearity as measured by ACLR for this GaN #1 PA. This PA is used to design a broadband differential PA with neutralization capacitors in the same GaN technology (i.e., GaN PA #2), which achieves similar PAE and BW in PEX EM simulations as the single-ended version, but with higher \(\sim\)3 dB gain and higher \(P_{OUT,SAT}\), as expected. Finally, a broadband 22 nm FD-SOI CMOS PA was designed, achieving excellent broadband results in the FR2 band with an RC feedback network and differential topology using neutralization capacitors. It achieves a 3-dB BW of 19.1-46.5 GHz and a good maximum PAE of 26.1% at 24 GHz and maintains a maximum PAE above 15.1% across the entire 24-39 GHz. Compared to the GaN #1 PA, increasing the 256-QAM 5G NR signal BW from 50 MHz to 9 \(\times\) 100 MHz degrades the ACLR linearity of the CMOS PA more, suggesting that the GaN PA may be able to deliver significantly higher \(P_{OUT,Linear}\) and \(P_{OUT,SAT}\) than their CMOS counterparts for mm-Wave 5G applications, albeit at a considerably higher cost with a lower level of monolithic integration.  
Conceptualization, J.M. and D.Y.C.L.; methodology, J.M. and D.Y.C.L.; validation, J.M. and D.Y.C.L.; formal analysis, J.M.; investigation, J.M.; resources, D.Y.C.L. and J.L.; data curation, J.M.; writing--original draft preparation, J.M.; writing--review and editing, J.M. and D.Y.C.L.; visualization, J.M.; supervision, D.Y.C.L.; funding acquisition, D.Y.C.L. All authors have read and agreed to the published version of the manuscript.  
This material is based on research sponsored by the Air Force Research Laboratory (AFRL) and the Defense Advanced Research Projects Agency (DARPA) under Grant Number FA8650-19-1-7902. The US Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon.  
Data contained within this article.  
The authors would like to thank [PERSON] for support in this work. We also sincerely thank the GlobalFoundries (GF) University Program, HRL for tapeout support and training, as well as the TTU Keh-Shew Lu Regents Chair Endowment fund.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.