# A 32-GHz Eight-Way Power Amplifier MMIC in 150 nm GaN HEMT Technology
## 3 Simulation and Measurement Results
The measured small-signal and large-signal performance are presented in Figure 9. The gain at 32 GHz is 16.4 dB, and the 3 dB gain bandwidth was 3.5 GHz between 31.3 and 34.8 GHz. The gate bias voltage was \(V_{\mathrm{GG}}=-1.55\) V and the drain supply voltage was \(V_{\mathrm{DD}}=25\) V with a total drain current of 410 mA. Figure 6: Photograph of the implemented 32 GHz power amplifier. Figure 8: A block diagram of the large-signal measurement setup. Figure 7: A block diagram of the small-signal measurement setup. Figure 9: _Cont._  
As shown in Figure 9a, the maximum gain was 16.9 dB at 32.7 GHz, and the 3 dB gain bandwidth was 3.5 GHz between 31.3 and 34.8 GHz with a sharp roll-off skirt. During the large signal test at 32 GHz under a 10% duty cycle and 1 ms pulse, the Psat was measured to be 38.3 dBm (6.76 W), and the power gain was 7.3 dB. The peak PAE was 19.3%, and the output of 1 dB gain compression point (OP1 dB) was around 28.5 dBm. The measurement results corresponded well with the simulations with small degradations at the high-frequency regime. Table 2 summarizes the performance of this work in comparison with the recently reported Ka-band power amplifiers. The proposed design has the best small-signal gain and 3 dB gain bandwidth performance compared with the other two-stage designs in the Ka-band. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \multirow{2}{*}{**Ref.**} & \multirow{2}{*}{**Tech.**} & \multirow{2}{*}{**Freq.** **(GHz)**} & \multirow{2}{*}{**Stages**} & \multicolumn{2}{c}{**Number of** **Power-Combining**} & \multirow{2}{*}{**BW** **(GHz)**} & \multirow{2}{*}{**Small-** **(GHz)**} & \multirow{2}{*}{**Point** **(dBm)**} & \multirow{2}{*}{**PAE** **(\%)**} & \multirow{2}{*}{**Area** **(mm\({}^{2}\))**} \\  & & & & & **Cells** & & & **Gain (dB)** & & \\ \hline \multirow{2}{*}{This} & 0.15 μm & \multirow{2}{*}{32} & \multirow{2}{*}{2} & \multirow{2}{*}{8} & \multirow{2}{*}{3.5} & \multirow{2}{*}{15.9} & \multirow{2}{*}{38.3} & \multirow{2}{*}{19.3} & \multirow{2}{*}{19.35} \\  & GaN/SiC & & & & & & & & \\ \multirow{2}{*}{[15]} & 0.15 μm & \multirow{2}{*}{26.5} & \multirow{2}{*}{2} & \multirow{2}{*}{16} & \multirow{2}{*}{2} & \multirow{2}{*}{43.4} & \multirow{2}{*}{19.8} & \multirow{2}{*}{23.6} \\  & GaN/SiC & & & & & & & \\ \multirow{2}{*}{[16]} & 0.2 μm & \multirow{2}{*}{31} & \multirow{2}{*}{2} & \multirow{2}{*}{16} & \multirow{2}{*}{2} & \multirow{2}{*}{10} & \multirow{2}{*}{42.6} & \multirow{2}{*}{17.4} & \multirow{2}{*}{22} \\  & GaN/SiC & & & & & & & & \\ \multirow{2}{*}{[17]} & 0.2 μm & \multirow{2}{*}{30} & \multirow{2}{*}{2} & \multirow{2}{*}{16} & \multirow{2}{*}{2} & \multirow{2}{*}{10} & \multirow{2}{*}{43.3} & \multirow{2}{*}{16} & \multirow{2}{*}{22} \\  & GaN/SiC & & & & & & & & \\ \multirow{2}{*}{[18]} & 0.15 μm & \multirow{2}{*}{29.5} & \multirow{2}{*}{3} & \multirow{2}{*}{4} & \multirow{2}{*}{3} & \multirow{2}{*}{28} & \multirow{2}{*}{37.8} & \multirow{2}{*}{34} & \multirow{2}{*}{5.6} \\  & GaN/SiC & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 2: Performance comparison of the Ka-band GaN HEMT power amplifiers. Figure 9: Simulation and measurement results of (**a**) small-signal performance and (**b**) large-signal performance.