Design of 3.3-3.7 GHz GaN HEMT balanced Class E power amplifier

Among power amplifiers, Class E circuits are very suitable for high efficiency power amplification applications in the radio-frequency. However, because of the single ended structure, these circuits suffer significant harmonic contents in the output and it is usually inevitable to design load matching networks very carefully to get low harmonic content. In this paper, the design of a balanced Class E power amplifier being symmetrically driven by two Class E circuits is studied. The balanced Class E circuit, under nominal operating conditions, has lower harmonic distortions, and the design of the impedance matching network for harmonic filtering becomes less critical. Practical design equations for Class E operation are given and simulation results graphically presented. It has been found that the proposed balanced GaN HEMT class-E amplifier can deliver the higher power, higher efficiency performances and lower harmonic distortion than single ended topologies for WiMax applications.