Microwave power amplifier load pull tuning analysis and measurements

Abstract

Started with some background information, Chapter 1 highlights the objective of this final year project. The purpose of this project is to identify the optimal load impedances for a power amplifier with regards to the various performances. Literature review is provided in Chapter 2. All the necessary and relative theories and principles are reviewed in this chapter. The basic operation principle of a BJT is explained firstly. GaAs HBT technology is then introduced. Following, classification of various power amplifiers is discussed, and their performances are compared. Next, 1dB Compression, Power Added Efficiency, Adjacent Channel Power Ratio are explained respectively. Subsequently, the purpose and application of the load-pull measurement is introduced. Finally, some functionalities of Vector Network Analyzer are illustrated. Chapter 3 consists of load-pull measurement procedures and measurement results. Before going into the procedures, some apparatus are briefly introduced. Load-pull measurement procedures include all the detailed steps and some considerations. In the end of this chapter, measurement results are presented. Software simulations are also conducted to model the physical measurement. The simulation details and results are described in Chapter 4. Upon all the measurements have been completed, the interpretation on the measurement results are presented in Chapter 5. The interpretation includes comparison and comments. Chapter 6 mentions some problems encountered during the measurement. Solutions for these problems are also provided. At the end of this report, the objective has been recalled. Some recommendations are also suggested.