Research on the CMOS Power Amplifier with Enhanced Efficiency for 5G Communication System Applications

• Main Authors: Zhi-Jia Huang, 黃致家
• Other Authors: 林坤佑
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/543bq5

碩士 === 國立臺灣大學 === 電信工程學研究所 === 107 === Several mm-Wave bands have been opened for 5G communication systems to achieve the Gb/s data transmission. Despite using the mm-Wave bands, the spectrum is still a limited resource. Therefore, to achieve high data rate in the limited bandwidth, high order modulation schemes are used, hence the AM-AM and AM-PM distortions need to be improved in the design of PA. Since the MIMO technology is used to enhance the efficiency of antenna radiation, the system would have many transmitters and PAs. Thus, the efficiency of PA is also an important design target. In this thesis, the traditional class-A/B/C amplifiers, harmonic-controlled amplifiers (Class F/F-1) and continuous-mode harmonic-controlled amplifiers (Continuous Class F/F-1) are introduced. The waveforms, maximum output power, efficiency and the impedance of fundamental and other harmonic frequencies will be discussed. The stability of differential amplifier is analyzed in differential and common modes, respectively. The stability of differential mode can be improved by the capacitor neutralization technique. However, the common-mode stability could be degraded due to neutralization capacitor. Using the series resistor in center tap of the gate transformer can decrease the common-mode gain and thus the common-mode stability can be improved without degrading the differential-mode performance. Finally, an example of 28 GHz differential power amplifier with capacitor neutralization technique is demonstrated. By using laser to cut the bypass capacitor of gate bias, the low-impedance at the center tap of the gate transformer becomes a high impedance due to the series resistor, the oscillation is thus removed. In order to get the broadband power performance, the continuous class-F topology is used. The continuous class-F harmonic-tuned output matching network is composed of a 1:1 transformer and a parallel series resonator to achieve the impedance condition of continuous class F. Besides, the gate bias of driver stage is designed for the reverse AM-PM distortion to compensate the of AM-PM distortion of the power stage. Finally, a dual-band class-F PA covering the 28/38 GHz bands is demonstrated with high efficiency. The dual-band class-F operation is obtained by dual-band class-F harmonic-tuned output matching network, which is composed of a 1:1 transformer, parallel multi-resonance networks, passive component, and parasitic components. The inductor of LC tank can be replaced by transformer to combine LC tank and transformer to minimum the area of output matching network.