# Frequency-Bounded Matching Strategy for Wideband LNA Design Utilising a Relaxed SSNM Approach
## 7 Conclusions  
This work extends the classical SSNM concept from narrowband theory to practical wideband application by introducing deliberate mismatches at the external ports; thus, \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref No.**} & \multirow{2}{*}{\begin{tabular}{c} **BW** \\ **(GHz)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Channel** \\ **Width** \\ **(nm)** \\ \end{tabular} } & \multicolumn{2}{c}{
\begin{tabular}{c} **Gate** \\ **Geometry** \\ **(Fingers \(\times\)** \\ **Width (um))** \\ \end{tabular} } & \multirow{2}{*}{**No. of** **Stages**} & \multirow{2}{*}{**S21 (dB)**} & \multirow{2}{*}{**S11, S22**} & \multirow{2}{*}{**NF (dB)**} & \multirow{2}{*}{**Topology**} \\ \cline{1-1} \cline{6-10}  & & & & & & & & \\ \hline
[3] & 26–36 & 100 & \(2\times 50\) & 4 & 33 & \(-12\), \(-12\) & 1.8 & Grounded FET \\ \hline
[8] & 25–35 & 150 & \(4\times 120\) & 3 & 28 & \(-10\), \(-15\) & 3 &
\begin{tabular}{c} Source \\ degeneration \\ \end{tabular} \\ \hline
[9] & 27–31 & 70 & \(4\times 30\) & 3 & 26 & \(-10\), \(-10\) & 1.6 &
\begin{tabular}{c} Source \\ degeneration \\ \end{tabular} \\ \hline
[10] & 14–31 & 150 & \(2\times 50\), \(1\times 50\) & 4 & 30–25 & \(-10\), \(-10\) & 1.25 &
\begin{tabular}{c} Drain-gate \\ RLC feedback \\ \end{tabular} \\ \hline
[11] & 27-34 & 250 & Not aai. & 5 & 30 & Not aai. & 2-3 & Grounded FET \\ \hline
[12] & 18.7–36.5 & 100 & \(4\times(25,75)\) & 2 & 15.9 & \(-10\), \(-10\) & 1.5–2.1 & R-L-C feedback \\ \hline
[13] & 18–43 & 100 & \(4\times(25,35,50)\) & 3 & 21.6 & \(-10\), \(-10\) & 1.8–2.7 & Feedback \\ \hline
[18] & 13–33 & 150 & \(6\times 40\) & 3 & 15.6–18.6 & \(-8\), \(-10\) & 1.05–2.8 &
\begin{tabular}{c} R-I-C shunt \\ feedback \\ \end{tabular} \\ \hline
[19] & 11–39 & 100 & \(4\times 25\) & 3 & 23 & \(-2\), \(-10\) & 2.1–3 &
\begin{tabular}{c} Transformer \\ feedback \\ \end{tabular} \\ \hline
[20] & 27–31 & 100 & Not aai. & 3 & 20 & \(-12\), \(-12\) & 1.6 &
\begin{tabular}{c} Filtering \\ matching \\ networks \\ \end{tabular} \\ \hline
[21] & 29–44 & 150 & Not aai. & 2 & 14.2 & \(-10\), \(-7\) & 2.3–3 &
\begin{tabular}{c} Forward \\ combining \\ \end{tabular} \\ \hline
[30] & 27–34 & 150 & Not aai. & 2 & 22.9 & \(-10\), \(-10\) & 2.7–3.2 & \
\begin{tabular}{c} Cascade, CS \\ degeneration \\ \end{tabular} \\ \hline This work & 28–34 & 150 & \(4\times 25\)\(\mu\)m & 3 & \(24\pm 1\) & \(-10\), \(-11\) & 2–2.5 &
\begin{tabular}{c} Source \\ degeneration \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 3: State-of-the-art GaAs LNA MMICs in Ka-band. it removes ambiguity in inter-stage mismatch levels. Each stage can function inside a frequency-bounded mismatch envelope described by IM-OM circles (derived from closed-form equations in the literature). Thanks to the relaxed SSNM conditions, the proposed graphical charts guide the designer across the entire band, while preserving an improved balance among gain, noise figure, and stability. An easy-to-follow strategy for wideband implementation using the relaxed SSNM condition is presented, supported by an MMIC demonstration. This approach significantly limits reliance on CAD-based optimisation when targeting wide frequency bands. The fabricated MMIC prototype achieves over 23 dB gain and 2-2.5 dB noise figure, from 28 GHz to 34 GHz, with measured results closely tracking simulations. The methodology naturally scales to wider bandwidths without modification and extends to N-stage cascaded LNAs. The improved IM-OM versus L\({}_{\text{S}}\) charts with induced mismatch scale provide a practical tool for selecting source degeneration inductors across multiple stages, and the frequency-bounded mismatch regions can be adapted for broader frequency spans. Future Work DirectionsFuture work will focus on integrating the envelope construction into an automated synthesis engine and validating the method across octave-band LNAs and reconfigurable front-ends.