An Efficiency Enhanced LINC Power Amplifier Using Pulse Modulation

• Main Authors: Min-Hsien Chuang 莊民賢, 莊民賢
• Other Authors: 陳昭宏
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/52984027516302984847

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 100 === In a modern communication system, a power amplifier plays an important role. Because the signal needs to be delivered efficiently, the design of a power amplifier will affect the entire system. In this thesis, we focus on the power efficiency. We conclude that the efficiency of the power amplifier is the key in a transmitter system, because it can reduce the system power consumption, and it can also prolong the standby time of handset devices. In order to improve the spectrum utilization, which increases the peak to average power ratio (PAR), linearity is required. However, for a power amplifier linearity and efficiency are not easy to achieve concurrently. Linearization techniques for power amplifiers can be adopted to improve the problem of linearity and power efficiency. This thesis presents a method for improving the efficiency of LINC (Linear Amplification using Nonlinear Components) by using pulse modulation, which theoretically can improve the linearity and power efficiency of a transmitter at the same time. The efficiency of the LINC power amplifier is related to the efficiency of the power amplifier and the power combiner. To further improve the efficiency of a LINC power amplifier with pulse modulation, replacement of the Wilkinson power combiner with the Chireix power combiner is proposed in this thesis. The experimental results show that the architecture proposed by this thesis does improve the drain efficiency. It can improve the efficiency for Wilkinson power combiner from 26.4% to 33.5%, and improve the Chireix power combiner from 50.7% to 65.2%. According to the experimental results, we know that the efficiency is definitely improved; therefore, this proposed method is a good architecture to enhance the efficiency. Further improvements to the linearity can be achieved through pre-distortion linearization.