Design of L-band class-F high efficiency carrier power amplifier

Abstract:

To solve the problem that the tradition class-F power amplifier is affected by transistor output capacitance and output inductance, resulting in complicated tuning circuit, a compact output harmonic tuned matching circuit is proposed. By analyzing the impedance characteristics of the fundamental wave matching circuit, equivalent to a finite reactance to the ground at the harmonic frequency, the reactance and the harmonic tuned matching circuit are co-designed to avoid introducing redundant elements and eliminate the influence of fundamental matching network on harmonic matching network, thus reducing the power amplifiers size. Finally, only an LC tuning network is introduced to realize the control of the output the second and third harmonics to improve the output efficiency. Based on this circuit structure, a high efficiency L-band power amplifier using 0.25 μm GaN HEMT transistor is designed and implemented on a 7 mm×8 mm Cu-Mo-Cu Carrier using internal matching technology. The measured results show that under the condition of a drain-source voltage of 28V and the input of 10% duty cycle pulse signal, the amplifier achieves the large-signal performance of 61%-63% PAE and over 26 dB power gain at a saturated power of 48.1-48.4 dBm within 1.18-1.42 GHz. The structure improves the efficiency and reduces the complexity of the circuit.