A Compact E-Band Power Amplifier With Gain-Boosting and Efficiency Enhancement

A compact E-band power amplifier (PA) with gain-boosting and efficiency enhancement technique is proposed and implemented in a 65-nm CMOS process. The proposed gain-boosting unit consists of cross-coupled transistors to introduce negative impedance and improve the quality factor of matching networks. Thus, the power gain and power-added efficiency (PAE) can be substantially improved at the power back-off (PBO) region. Neutralization capacitors are also adopted to improve power gain, reverse isolation, and stability as well. The proposed PA achieves a measured PAE of 22.37%, a Psat of 14.29 dBm, and an O P
₁
dB of 12.03 dBm with a maximum power gain of 31 dB when the gain-boosting unit turns on. By adjusting the control voltages of the gain-boosting unit, the measured peak gain increases from 26 to 31 dB, and a maximum of 1.7-dBm output power and 5.2% PAE improvement at the input power corresponding to I P
₁
dB under the gain-boosting unit turned off are achieved. Furthermore, modulation measurement shows that the proposed E-band PA supports 16-Gb/s 16-QAM and 9.6-Gb/s 64-QAM modulated signals with error vector magnitudes (EVMs) of -17.7 dB/-23.1 dB and average output powers of 8.75 dBm/10.41 dBm, respectively. The core area and dc power consumption of the PA are only 0.025 mm
²
and 120 mW.