Design of High Efficiency Power Amplifier for RFID Readers

Abstract

In RFID reader systems, power amplifier plays a critical rule for efficiency enhancement. A high efficiency power amplifier may not only increase the life expectancy of portable RFID devices but also reduce the reliance on heat sinks. Heat sinks usually occupy plenty of space and lead to packing difficulties. A well-designed power amplifier with high efficiency and output power may also increase the reading range of RFID and system reliability, especially for the applications requiring long reading range (e.g. vehicle tagging in complicated traffics) or in a lossy environment (e.g. in sensing in rainy weather). This chapter systematically introduces the typical power amplifiers classified as Class A, AB, B, E, and F. The principles of Class F are emphasized due to its outstanding performance in efficiency enhancement. A practical design example is also presented, and also some recent typical techniques for improving the performances of Class F power amplifier are summarized.