# A 37-40 GHz 6-Bits Switched-Filter Phase Shifter Using 150 nm GaN HEMT
## 4 Conclusions  
In this paper, a phase shifter was designed and fabricated to operate within the 5G NR standard n260 frequency range (37-40 GHz) using the 150 nm GaN HEMT process. The fabricated phase shifter is structured as a 6-bit switch filter, demonstrating impressive performance metrics: an RMS phase error of less than 5.36 degrees, an RMS gain error of under 3.21 dB, and a robust IP1 dB exceeding 10 dBm. This high IP1 dB value proves advantageous for seamless integration with high-power RF circuits.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **This Work** & [11] & [12] & [13] & [14] & [15] & [5] & [19] \\ \hline \multirow{2}{*}{Process} & \multirow{2}{*}{150 nm GaN} & 250 nm & 150 nm & 65 nm & 28 nm & 65 nm & 65 nm & 22 nm \\  & & BiCMOS & GaAs & CMOS & CMOS & CMOS & CMOS & FD SOI \\ \hline \multirow{2}{*}{Topology ***} & \multirow{2}{*}{STPS} & \multirow{2}{*}{APN} & \multirow{2}{*}{STPS} & \multirow{2}{*}{STPS} & \multirow{2}{*}{STPS} & \multirow{2}{*}{STPS} & \multirow{2}{*}{PVSPS} & \multirow{2}{*}{AVSPS} \\ \cline{1-1} \cline{5-10}  & & & & & & & & \\ \hline Frequency (GHz) & 37–40 & 37–43 & 36–39 & 38–40.5 & 29–37 & 35–41.9 & 32–40 & 24–36 \\ \hline FBW (\%) & 7.8 & 15 & 8 & 6.4 & 24 & 17.95 & 22 & 40 \\ \hline No. of Bit & 6 & 2 & 4 & 5 & 4 & 5 & 7 & 5 \\ \hline Resolution (\({}^{\circ}\)) & 5.625 & 45 & 22.5 & 11.25 & 22.5 & 11.25 & & \\ \hline Gain (dB) & \(-10.5\) & \(-13.25\) & \(-10.6\) & \(-14.5\) & \(-12.8\) & \(-7.56\) & \(-17.5\) & \(-6.6\) \\ \hline Gain var. (dB) & \(\pm 5.5\) & \(\pm 0.75\) & \(\pm 2.9\) & \(\pm 2\) & \(\pm 2.5\) & \(\pm 0.22\) & \(\pm 0.6\) & \(\pm 1.6\) \\ \hline Gain/Bit (dB) & \(-1.75\) & \(-6.63\) & \(-2.65\) & \(-2.9\) & 3.2 & \(-1.5\) & \(-2.5\) & \(-1.32\) \\ \hline IP1 dB (dBm) & \textgreater{}10–16 ** & N/A & N/A & N/A & 5 & \textgreater{}7.1 & 10.2–13.5 & \textless{}4 \\ \hline RMS PE (\({}^{\circ}\)) & \textless{}5.36 & \textless{}5 & \textless{}9.7 & \textless{}4 & \textless{}8.8 & \textless{}5.9 & \textless{}1.6 & \textless{}4 \\ \hline RMS GE (dB) & \textless{}3.21 & \textless{}0.5 & \textless{}1.81 & \textless{}1.4 & N/A & \textless{}0.22 & \textless{}0.36 & \textless{}0.6 \\ \hline Pdc (mW) & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 7.2 \\ \hline Area (mm\({}^{2}\)) & 3.36 * & 0.28 & 0.65 & 0.4 & 0.08 & 0.13 & 0.14 & 0.58 \\ \hline \hline \end{tabular}  
* Area with including bondpads; ** Simulation result; *** APN: All-Pass Network; STPS: Switched-Type PS; AVSPS: Active Vector Sum PS; PVSPS: Passive Vector Sum PS.  
\end{table}
Table 1: Performance Summary and Comparison with the State-of-the-Art Phase Shifters.  
Figure 7: RMS error: (**a**) Gain; (**b**) Phase.  
**Author Contributions:** Conceptualization, E.-G.L. and C.-Y.K.; Data curation, J.-H.S. and E.-G.L.; Formal analysis, J.-H.S., E.-G.L. and C.-Y.K.; Funding acquisition, C.-Y.K.; Investigation, J.-H.S., J.-E.L. and J.-T.S.; Methodology, [PERSON]-[PERSON], [PERSON]-[PERSON] and [PERSON]-Y.K.; Project administration, C.-Y.K.; Resources, C.-Y.K.; Software, [PERSON] and [PERSON]; Supervision, C.-Y.K.; Validation, [PERSON]-[PERSON], [PERSON] and [PERSON]-[PERSON]; Visualization, [PERSON], [PERSON]-[PERSON] and [PERSON]-[PERSON]; Writing--original draft, [PERSON]-[PERSON]; Writing--review and editing, [PERSON]-[PERSON] and [PERSON]-[PERSON]. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2021R1A4A1032580).  
**Conflicts of Interest:** The authors report that there are no competing interest to declare.