PhD project: Power Amplifier Techniques for Mobile Communication

The project focuses on the new techniques in modeling and designing of RF power amplifiers (PA) for mobile communication.



In system level design of transmitters, accurate behavioral models of different building blocks are required. However, for highly nonlinear components the classic methods of behavioral modeling are not always suitable in practice. The X-parameter concept was developed to solve this problem. As a mathematically correct superset of S-parameters, X-parameters characterize nonlinear devices, which are excited by large signals. The first goal of this project is to develop a behavioral model of a highly linear power amplifier using X-parameters and further investigate how this model can be directly used in PA linearization.



In the second half of the project, the goal is to develop a digitally controlled PA, which can be dynamically adjusted according to the specific requirements (high power-added-efficiency (PAE), output power or linearity). In wireless transmitter systems the PA is a critical component because it consumes a considerable amount of power due to its relatively low power efficiency. At the same time, it is also one of the most linearity-sensitive parts as it is the last block before the antenna. For the PAs, there is always a demand of high PAE, high enough output power that is required and high linearity. One way to maximize a selected performance indicator is to digitally control/modify the PA structure. The digitally controlled PA concept may offer the on-demand tradeoff between PAE, output power and the linearity. In addition to that, novel PA topologies which might be suitable for LTE, such as multimode PA and inverse Class E PA, are also investigated.



This project is a part of the 4GMCT (4th Generation Mobile Communication and Test Platform) project. 4GMCT project is a four year project. Aalborg University is a member of the project and will cooperate with Infineon Technologies and Agilent Technologies.