Research And Inverse Class E Class E RF Power Amplifier

The RF transmitter is one of the most important parts of the wireless communication system. Moreover, the RF power amplifier is an essential component of the RF transmitter. The performance index of the RF power amplifier such as efficiency, gain and linearity will largely decide the whole performance of the RF transmitter. Therefore, the study of the RF power amplifier has always been a hotspot in the RF field.However, the traditional linear RF power amplifiers which are always inefficient that cannot meet the demand of high efficiency required by modern wireless communication system. That’s why class E and inverse class E power amplifier were proposed. In the class E and inverse class E power amplifier, the active device operates as an on/off switch, and the shapes and relative timing of the current and voltage waveforms are such that high current and high voltage do not occur simultaneously. Thus, the class E and inverse class E power amplifier can obtain100%efficiency theoretically.Firstly, this paper introduces the application, performance index and classification of the RF power amplifier, as well as the fundamental principles, pros and cons of all kinds of the RF power amplifiers.Then, the circuit principle of the class E and inverse class E power amplifier is interpreted. The mathematical derivation of the class E power amplifier is also presented. The purpose of it is to obtain the calculation formula of the circuit elements. Furthermore, design examples are given to illustrate the design steps of the class E and inverse class E power amplifier.Next, a broadband class E power amplifier based on GaN transistor is simulated, which can provide a power-added efficiency of no less than53%and a power gain of more than11dB in a frequency bandwidth of1.2～2.2GHz. However, the gain flatness of this broadband class E power amplifier is so poor that a special negative feedback network based on RLC series resonance is proposed to improve the gain flatness.Finally, a2.4GHz cascode class E and inverse class E power amplifier based on TSMC0.18μm CMOS technology is discussed and simulated respectively to show the advantages of the inverse class E power amplifier in CMOS circuit.