# A Ku-Band GaAs Multifunction Transmitter and Receiver Chipset
## 5 Conclusions  
In this paper, a high-gain multifunction transmitter and receiver chipset operating over the Ku-band is presented. MPA and LNA are integrated together with attenuator and phase shifter to achieve high output power and a low noise figure. In addition, SPC is integrated to control the 5-bit attenuator and 4-bit phase shifter, thereby facilitating the digital interconnection. The multifunction chipset was fabricated in a 0.25-um GaAs pHEMT technology. The measurement results show that the multifunction chipset offers 15.5-dB attenuation with 0.5-dB step and 360\({}^{\circ}\) phase shift with 22.5\({}^{\circ}\) step. The multifunction transmitter exhibits a peak gain of 16.5 dB and OP1 dB of 19.2 dBm. The multifunction  
Figure 23: Phase shift performance of the multifunction receiver: (a) phase shift in the 16 phase states, (b) RMS phase and parasitic amplitude errors.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Ref.**} & \multirow{2}{*}{**Process**} & \multirow{2}{*}{\
\begin{tabular}{c} **Freq.** \\ **(GHz)** \\ \end{tabular} } & \multirow{2}{*}{**Architecture**} & \multirow{2}{*}{
\begin{tabular}{c} **Gain\({}_{\text{MAX}}\)1** \\ **(dB)** \\ \end{tabular} } & \multirow{2}{*}{**OP1 dB**} & \multirow{2}{*}{**NE \({}^{2}\)(dB)**} & \multirow{2}{*}{**PS/ATT**} & \multirow{2}{*}{**RMS Atten.**} & \multirow{2}{*}{**RMS Phase**} & \multirow{2}{*}{**Chip Size**} \\  & & & & & & & & & & \\ \hline
[1] & 0.5-μm GaAs & 12-18 & ATT + PS + SPC & -13 & - & - & 4/4 & 0.5 & 3.5 & 7.6 \\
[8] & 0.25-μm GaAs & 10-13 & LNA + PS + & 12\({}^{\star}\) & 3.3612.25 GHz 2 & 4/- & - & \textless{}6 & 3.0 \\
[8] & pHEMT & 13.5-15.5 & PS + MA + & \textgreater{}10 & 12.5814.5 GHz - & 4/- & - & \textless{}3 & 3.0 \\
[10] & 0.18-μm GaAs & 8.6-10 & + AMR + PS + & 11.9 (Tk) & - & 6/6 & - & - & 14.8 \\  & pHEMT & 8.6-10 & AMP + PS + SPC & 12.3 (Rx) & - & - & 6/6 & - & - & 14.8 \\ \hline
[11] & 0.18-μm GaAs & \begin{tabular}{c} 5-μm GaAs \\ pHEMT \\ \end{tabular} & \begin{tabular}{c} SW + AMP, + \\ PS/HT \\ \end{tabular} & \begin{tabular}{c} SW + AMP, + \\ PS/HT \\ \end{tabular} & \
\begin{tabular}{c} SW + AMP, + \\ PS/HT \\ \end{tabular} &
\begin{tabular}{c} * \\ PS + SPCreceiver exhibits a peak gain of 17.3 dB and noise figure of 2.5 dB. The multifunction chipset can be used for Ku-band phased array systems for military and satellite applications.  
Methodology, H.L., Y.K., K.P., and S.J.; validation, H.L. and S.J.; investigation, H.L., Y.K., I.L., D.K., K.P., and S.J.; resources, H.L., Y.K., I.L., D.K., and K.P.; data curation, H.L., Y.K., I.L., D.K., and K.P.; writing--original draft presentation, H.L., Y.K., D.K., K.P., and S.J.; writing--review and editing, H.L., and S.J.; supervision, S.J.; project administration, S.J.; funding acquisition, S.J. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the MSIT (Ministry of Science and ICT), Korea, under the ITRC (Information Technology Research Center) support program (IITP-2020-0-01749-001) supervised by the IITP (Institute of Information & Communications Technology Planning & Evaluation).  
The authors declare no conflict of interest.