Design of 2.45-GHz High-Efficiency Miniaturized Power Oscillator Using GaN HEMT

Abstract

This study presents a method for designing a highly efficient miniaturized power oscillator with gallium nitride high electron mobility transistor (GaN HEMT). A harmonic-tuning highly efficient power amplifier (PA) using GaN HEMT is designed firstly by finding optimal fundamental, 2nd and 3rd harmonic load impedances. After the performance of PA meets the requirements, the feedback circuit that is made of a hairpin resonator and a coupler is studied based on the power gain of PA and the required frequency. Both the size of the PA and the feedback circuit should be taken into account to minimize the oscillator at last. Finally, the PA and feedback circuit are combined into a power oscillator. Through this way, the highly efficient miniaturized power oscillator with a size of 2.7*4.9 cm2 fabricated on substrate of FR4 outputs 37.7 dBm power and 72% efficiency at 2.4518 GHz under the bias condition of Vgs = - 3.21V, Vds = 28V, Ids = 25mA.