High-Efficiency Microwave Power Amplifier with Higher Harmonics Level Control on Basis of Defected Ground Structure Resonators

In this paper the class-E amplifier with higher harmonic control is presented. The aim of the harmonic control is to form required load impedances to obtain Class-E conditions. Two output networks were calculated, fabricated, and experimentally measured to validate the proposed approach. The first uses two H-shaped resonators in ground plane of microstrip line and controls 2nd and 3rd harmonics. The second uses three coupled narrow slot resonators in ground plane of microstrip line and controls 2nd, 3rd, and 4th harmonics. Both output networks realize higher harmonic control by means of Defected Ground Structures (DGS). The harmonic control is used to form flatted drain waveform in order to decrease maximum drain voltage and minimize transistor utilization factor at the operating frequency 2.14 GHz.