基于GaN器件的平衡式逆F类功率放大器的研究与设计

针对功率放大器效率低和输入输出端反射损耗较大的缺陷，采用平衡式结构研究了工作于2.6 GHz的逆F类功率放大器，并基于GaN器件CGH40010F设计该放大器验证电路。根据功放管输出寄生参数的等效网络，将负载阻抗转换到封装参考面上，在输出匹配电路中对二、三次谐波进行抑制处理。并且考虑栅源寄生电容对输入信号的影响，在输入拓扑结构中加入二次谐波抑制电路，进一步提高了放大器的效率。同时，在栅漏极偏置电路中，采用扇形微带线代替短路电容，使电路结构更为紧凑。经仿真优化，采用Rogers4350b板材制作该功放电路板。实测表明，饱和输出功率为42.32 dBm，最大漏极效率为77.91%，最大功率附加效率(power added efficiency, PAE)达到72.16%，输入输出驻波系数(voltage standing wave ratio, VSWR)均小于2。实测结果与仿真数据基本吻合，验证了设计方法的可行性。

Research and design of the balanced inverse class-F power amplifier based on GaN devices

In order to deal with low efficiency and large input/output return loss of power amplifier, a 2.6 GHz balanced inverse Class F power amplifier test circuit based on GaN device CGH40010F was designed. According to the approximated equivalent network of output parasitics, the load impedances are transferred into the package plane, the second and third harmonic are suppressed in the output matching circuit. Taking into account the effect of the gate source parasitic capacitance on the input signal, the second harmonic suppression circuit is added into the input topology to further enhance the efficiency of the power amplifier. Meanwhile, the circuit size is smaller and compact by utilizing microstrip radial stub in the bias circuit. By making simulation and optimization, the power amplifier circuit board is made of Rogers4350b.The measure results demonstrate that the PA provides saturated output power of 42.32 dBm with maximum PAE of 72.16% and maximum drain efficiency of 77.91%, input and output standing wave ratio is less than 2. Experimental results are in good agreement with the simulation results, which confirmed feasibility of design methodology.