一种S波段逆F类滤波功率放大器设计

Design of an S-band inverse class-F filtering power amplifier

为解决通信系统中滤波器与功率放大器级联后带来的级联损耗问题,本文将带通滤波器集成到功率放大器的输出匹配电路中,精简了阻抗匹配和连接结构,实现了尺寸缩减和功耗降低;采用谐波控制和寄生参数补偿电路,实现了功率放大器的逆F类工作状态;基于三角环和阶跃阻抗混合结构,实现一种新型微带线带通滤波器,带内损耗约为0.55 dB,2个零点分布在通带两侧。理论分析了实现滤波器任意输入阻抗的方法,并通过实测验证了滤波器的低损耗、高选择性和阻抗匹配。本文设计、加工并实测了一款S波段滤波功率放大器,测试结果显示其通带内效率达68.7%,输出功率39.8 dBm,二次谐波的抑制超过60 dB。该功率放大器性能优越性,在通信发射系统中具有良好的应用前景。

In order to solve the cascading loss caused by the cascade of filter and power amplifier in the communication system,in this paper,the bandpass filter is integrated into the output matching circuit of amplifier,which facilitates the impedance matching and connection structure,resulting in a reduction of both dimensions and power consumption.Using a harmonic control circuit as well as a parasitic parameter compensation circuit,the power amplifier operates in its inverse class-F state successfully.A novel microstrip bandpass filter based on a hybrid structure of triangular ring and step impedance resonator is implemented.Its in-band loss is 0.55 dB or so and there are two transmission zeros distributed on both sides of the passband.Theoretical analysis is carried out to realize an arbitrary input impedance of the filter.The filter’s performance,such as low loss,high selectivity and impedance matching,are all verified with measurements.An S-band filtering power amplifier is designed,fabricated and measured.The test results show that the maximum efficiency reaches 68.7%with 39.8 dBm output power.The second harmonic suppression reaches 60 dB,which presents good future applications in the communication transmission system.