# An MMIC LNA for Millimeter-Wave Radar and 5G Applications with GaN-on-SiC Technology
## 4 Conclusions  
In this research paper, we present a comprehensive study on the design and implementation of a three-stage broadband MMIC LNA. The LNA operates in the frequency band of 24.25-29.5 GHz and is fabricated using an advanced 0.15 \(\upmu\)m GaN-on-SiC HEMT process. To meet the requirements for gain and NF, an in-depth analysis of the device characteristics is conducted in Section 2.1. This analysis allows us to gain a deep understanding of the device behavior and select appropriate design strategies to optimize the LNA performance.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Ref.** & **Process** & **Freq (GHz)** & **Gain (dB)** & **NF (dB)** & **Area (mm\({}^{2}\))** & **Power (mW)** & **Stages** \\ \hline
[20] & CMOS & 15.8–30.3 & 8.5–10.2 & 3.3–5.7 & 0.18 & 12.4 & 2 \\ \hline
[21] & CMOS & 21.2–24 & 16.5–19.1 & 3.6–4.2 & 0.35 & 0.99 & 2 \\ \hline
[22] & CMOS & 26–31 & 9.6–12 & 5.0–5.45 & 0.19 & 14.4 & 3 \\ \hline
[23] & CMOS & 21–34.5 & 10.5 & 2.4–3.9 & 0.03 & 4 & 2 \\ \hline
[24] & GaAs & 2–42 & 12.6–14.1 & 2.4 & 1.53 & 129 & 11 \\ \hline
[25] & GaN-on-Si & 35–37 & 19.7 & 3.7 & 5.21 & / & 4 \\ \hline
[26] & GaN-on-Si & 18–22.5 & 16.5–17.9 & 2.0–2.3 & 2.2 & 1100 & 2 \\ \hline
[27] & GaN-on-SiC & 27–31 & 12 & 3.7–3.9 & 4.08 & 560 & 4 \\ \hline
[28] & GaN-on-SiC & 27.5–28.5 & 18 & 4 & 6 & 6000 & 4 \\ \hline
[29] & GaN-on-SiC & 1–25 & 10–13 & 3.3–5 & 1.44 & 900 & 2 \\ \hline This Work & GaN-on-SiC & 24.25–29.5 & 18.3–20.2 & 2.5–3.1 & 3.75 & 500 & 3 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Performances comparison with previously published works.  
Figure 15: Measurement results of stability factors (k and b) for the fabricated MMIC LNA.  
Several stability enhancement measures are proposed in this paper, including the implementation of source degeneration, RC series networks, and RF chokes. These measures effectively improve the stability of the amplifier, preventing oscillations and ensuring reliable operation across the desired frequency range. To achieve a balance between low noise and wide bandwidth, hybrid-MNs with a co-design strategy are adopted. This approach combines different types of matching networks to maximize the benefits of each, resulting in improved overall performance. The proposed 3.75 mm\({}^{2}\) MMIC LNA exhibits a measured small signal gain of 18.3-20.2 dB and a minimal NF of 2.5 dB in the 24.25-29.5 GHz frequency range. It offers excellent amplification capabilities while maintaining a low NF, making it well-suited for sensitive receiver applications in these fields. Through detailed analysis, innovative stability enhancement measures, and the adoption of a hybrid-MNs design strategy, we have successfully designed and implemented a broadband MMIC LNA that meets the demanding requirements of 5G and millimeter-wave radar applications. The experimental results validate the effectiveness of our approach, highlighting the potential for further advancements and applications in the field of integrated circuit design and RF engineering.  
Conceptualization, C.H., X.W., H.L. and Z.Z.; methodology, C.H., X.W., H.L. and Z.Z.; software, C.H., X.W. and Z.Z.; validation, C.H., X.W. and Z.Z.; formal analysis, C.H., X.W. and Z.Z.; investigation, C.H. and Z.Z.; resources, Z.Z. and G.Z.; data curation, C.H. and Z.Z.; writing--original draft preparation, C.H.; writing--review and editing, C.H., Z.Z. and G.Z.; visualization, C.H. and Z.Z.; supervision, Z.Z. and G.Z.; project administration, Z.Z. and G.Z.; funding acquisition, Z.Z. and G.Z. All authors have read and agreed to the published version of the manuscript.  
The National Key R&D Program of China (Grant No. 2018 YFB1802100), the National Natural Science Foundation of China (Grant No. 61974035), and the Guangdong Local Inno. Research Team of Pearl River Talent Program (Grant No. 2017 BT01X168).  
Not applicable.  
The data may be obtained from the authors upon request.  
The authors declare no conflict of interest.