改进型宽带Doherty功率放大器的设计

根据Doherty技术,设计了一款改进型宽频带功率放大器。在设计过程中,分析了λ/4线对Doherty功率放大器(DPA)的影响。通过对阻抗比的研究,在理论上延拓了功放的带宽。此外,应用不对称功率输入结构来克服阻抗比变化所带来的非理想调制效应。为了证明文中的理论分析,采用飞思卡尔公司的LDMOSFET功放管MRF6S20010,最终设计实现了一款工作于1 900～2 200MHz的宽频带Doherty功率放大器。测试结果显示,改进型宽带功放相对于传统Doherty功率放大器有很大的优势,可用于无线通信领域。

Advanced Design of a Wideband Doherty Power Amplifier

According to the Doherty′s technology,an advanced wideband power amplifier is introduced.During designing process,the effect of quarter-wavelength line on the Doherty power amplifier(DPA) were analyzed.The band of the amplifier was extended theoretically through the research of impedance ratio.Furthermore,for the sake of overcoming the nonlinear modulation effect introduced by the changed impedance ratio,the asymmetrical input power divider was employed.In order to prove the theoretical analysis,a DPA employing Freescale′s laterally diffused metal oxide semiconductor field effect transistor(LDMOS FET) MRF6S20010 worked at the frequency of 1 900～2 200 MHz was designed and realized finally.The measurements show the proposed DPA exhibits huge advantage over the traditional one and it can be applied to wireless communication.